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Guias de estudo > ALGEBRA / TRIG I

Problem Set: Multi-Step Linear Equations

THIS IS OPTIONAL ADDITIONAL PRACTICE

Solve Equations Using the Subtraction and Addition Properties of Equality

In the following exercises, determine whether the given value is a solution to the equation. Is y=13y=\Large\frac{1}{3} a solution of 4y+2=10y?4y+2=10y? Is x=34x=\Large\frac{3}{4} a solution of 5x+3=9x?5x+3=9x? Is u=−12u=-\Large\frac{1}{2} a solution of 8u−1=6u?8u - 1=6u? Is v=−13v=-\Large\frac{1}{3} a solution of 9v−2=3v?9v - 2=3v? In the following exercises, solve each equation. x+7=12x+7=12 y+5=−6y+5=-6 b+14=34b+\Large\frac{1}{4}\normalsize =\Large\frac{3}{4} a+25=45a+\Large\frac{2}{5}\normalsize =\Large\frac{4}{5} p+2.4=−9.3p+2.4=-9.3 m+7.9=11.6m+7.9=11.6 a−3=7a - 3=7 m−8=−20m - 8=-20 x−13=2x-\Large\frac{1}{3}\normalsize=2 x−15=4x-\Large\frac{1}{5}\normalsize =4 y−3.8=10y - 3.8=10 y−7.2=5y - 7.2=5 x−15=−42x - 15=-42 z+5.2=−8.5z+5.2=-8.5 q+34=12q+\Large\frac{3}{4}\normalsize =\Large\frac{1}{2} q=−14q=-\Large\frac{1}{4} p−25=23p-\Large\frac{2}{5}\normalsize =\Large\frac{2}{3} y−34=35y-\Large\frac{3}{4}\normalsize =\Large\frac{3}{5} y=2720y=\Large\frac{27}{20} Solve Equations that Need to be Simplified In the following exercises, solve each equation. c+3−10=18c+3 - 10=18 m+6−8=15m+6 - 8=15 17 9x+5−8x+14=209x+5 - 8x+14=20 6x+8−5x+16=326x+8 - 5x+16=32 8 −6x−11+7x−5=−16-6x - 11+7x - 5=-16 −8n−17+9n−4=−41-8n - 17+9n - 4=-41 −20 3(y−5)−2y=−73\left(y - 5\right)-2y=-7 4(y−2)−3y=−64\left(y - 2\right)-3y=-6 2 8(u+1.5)−7u=4.98\left(u+1.5\right)-7u=4.9 5(w+2.2)−4w=9.35\left(w+2.2\right)-4w=9.3 1.7 −5(y−2)+6y=−7+4-5\left(y - 2\right)+6y=-7+4 −8(x−1)+9x=−3+9-8\left(x - 1\right)+9x=-3+9 −2 3(5n−1)−14n+9=1−23\left(5n - 1\right)-14n+9=1 - 2 2(8m+3)−15m−4=3−52\left(8m+3\right)-15m - 4=3 - 5 −4 −(j+2)+2j−1=5-\left(j+2\right)+2j - 1=5 −(k+7)+2k+8=7-\left(k+7\right)+2k+8=7 6 6a−5(a−2)+9=−116a - 5\left(a - 2\right)+9=-11 8c−7(c−3)+4=−168c - 7\left(c - 3\right)+4=-16 −41 8(4x+5)−5(6x)−x=538\left(4x+5\right)-5\left(6x\right)-x=53 6(9y−1)−10(5y)−3y=226\left(9y - 1\right)-10\left(5y\right)-3y=22 28

Translate to an Equation and Solve

In the following exercises, translate to an equation and then solve. Five more than xx is equal to 2121. The sum of xx and −5-5 is 3333. x + (−5) = 33; x = 38 Ten less than mm is −14-14. Three less than yy is −19-19. y − 3 = −19; y = −16 The sum of yy and −3-3 is 4040. Eight more than pp is equal to 5252. p + 8 = 52; p = 44 The difference of 9x9x and 8x8x is 1717. The difference of 5c5c and 4c4c is 6060. 5c − 4c = 60; 60 The difference of nn and 16\Large\frac{1}{6} is 12\Large\frac{1}{2}. The difference of ff and 13\Large\frac{1}{3} is 112\Large\frac{1}{12}. f−13=112;512f-\Large\frac{1}{3}\normalsize =\Large\frac{1}{12}\normalsize ;\Large\frac{5}{12} The sum of −4n-4n and 5n5n is −32-32. The sum of −9m-9m and 10m10m is −25-25. −9m + 10m = −25; m = −25

Translate and Solve Applications

In the following exercises, translate into an equation and solve. Pilar drove from home to school and then to her aunt’s house, a total of 1818 miles. The distance from Pilar’s house to school is 77 miles. What is the distance from school to her aunt’s house? Jeff read a total of 5454 pages in his English and Psychology textbooks. He read 4141 pages in his English textbook. How many pages did he read in his Psychology textbook? Let p equal the number of pages read in the Psychology book 41 + p = 54. Jeff read pages in his Psychology book. Pablo’s father is 33 years older than his mother. Pablo’s mother is 4242 years old. How old is his father? Eva’s daughter is 55 years younger than her son. Eva’s son is 1212 years old. How old is her daughter? Let d equal the daughter’s age. d = 12 − 5. Eva’s daughter’s age is 7 years old. Allie weighs 88 pounds less than her twin sister Lorrie. Allie weighs 124124 pounds. How much does Lorrie weigh? For a family birthday dinner, Celeste bought a turkey that weighed 55 pounds less than the one she bought for Thanksgiving. The birthday dinner turkey weighed 1616 pounds. How much did the Thanksgiving turkey weigh? 21 pounds The nurse reported that Tricia’s daughter had gained 4.24.2 pounds since her last checkup and now weighs 31.631.6 pounds. How much did Tricia’s daughter weigh at her last checkup? Connor’s temperature was 0.70.7 degrees higher this morning than it had been last night. His temperature this morning was 101.2101.2 degrees. What was his temperature last night? 100.5 degrees Melissa’s math book cost {$22.85} less than her art book cost. Her math book cost {$93.75}. How much did her art book cost? Ron’s paycheck this week was {$17.43} less than his paycheck last week. His paycheck this week was {$103.76}. How much was Ron’s paycheck last week? $121.19

everyday math

Baking

Kelsey needs 23\Large\frac{2}{3} cup of sugar for the cookie recipe she wants to make. She only has 14\Large\frac{1}{4} cup of sugar and will borrow the rest from her neighbor. Let ss equal the amount of sugar she will borrow. Solve the equation 14+s=23\Large\frac{1}{4}\normalsize +s=\Large\frac{2}{3} to find the amount of sugar she should ask to borrow.

Construction

Miguel wants to drill a hole for a 58-inch\Large\frac{5}{\text{8}}\normalsize\text{-inch} screw. The screw should be 112\Large\frac{1}{12} inch larger than the hole. Let dd equal the size of the hole he should drill. Solve the equation d+112=58d+\Large\frac{1}{12}\normalsize =\Large\frac{5}{8} to see what size the hole should be. d=1324d=\Large\frac{13}{24}
 

writing exercises

Is −18-18 a solution to the equation 3x=16−5x?3x=16 - 5x? How do you know? Write a word sentence that translates the equation y−18=41y - 18=41 and then make up an application that uses this equation in its solution. Answers will vary.
 

Solve Equations Using the Division and Multiplication Properties of Equality

Solve Equations Using the Division and Multiplication Properties of Equality

In the following exercises, solve each equation for the variable using the Division Property of Equality and check the solution. 8x=328x=32 7p=637p=63 9 −5c=55-5c=55 −9x=−27-9x=-27 3 −90=6y-90=6y −72=12y-72=12y −7 −16p=−64-16p=-64 −8m=−56-8m=-56 7 0.25z=3.250.25z=3.25 0.75a=11.250.75a=11.25 15 −3x=0-3x=0 4x=04x=0 0 In the following exercises, solve each equation for the variable using the Multiplication Property of Equality and check the solution. x4=15\Large\frac{x}{4}\normalsize =15 z2=14\Large\frac{z}{2}\normalsize =14 28 −20=q−5-20=\Large\frac{q}{-5} c−3=−12\Large\frac{c}{-3}\normalsize =-12 36 y9=−6\Large\frac{y}{9}\normalsize =-6 q6=−8\Large\frac{q}{6}\normalsize =-8 −48 m−12=5\Large\frac{m}{-12}\normalsize =5 −4=p−20-4=\Large\frac{p}{-20} 80 23y=18\Large\frac{2}{3}\normalsize y=18 35r=15\Large\frac{3}{5}\normalsize r=15 25 −58w=40-\Large\frac{5}{8}\normalsize w=40 24=−34x24=-\Large\frac{3}{4}\normalsize x −32 −25=110a-\Large\frac{2}{5}\normalsize =\Large\frac{1}{10}\normalsize a −13q=−56-\Large\frac{1}{3}\normalsize q=-\Large\frac{5}{6} 5/2 Solve Equations That Need to be Simplified In the following exercises, solve the equation. 8a+3a−6a=−17+278a+3a - 6a=-17+27 6y−3y+12y=−43+286y - 3y+12y=-43+28 y = −1 −9x−9x+2x=50−2-9x - 9x+2x=50 - 2 −5m+7m−8m=−6+36-5m+7m - 8m=-6+36 m = −5 100−16=4p−10p−p100 - 16=4p - 10p-p −18−7=5t−9t−6t-18 - 7=5t - 9t - 6t t=52t=\Large\frac{5}{2} 78n−34n=9+2\Large\frac{7}{8}\normalsize n-\Large\frac{3}{4}\normalsize n=9+2 512q+12q=25−3\Large\frac{5}{12}\normalsize q+\Large\frac{1}{2}\normalsize q=25 - 3 q = 24 0.25d+0.10d=6−0.750.25d+0.10d=6 - 0.75 0.05p−0.01p=2+0.240.05p - 0.01p=2+0.24 p = 56

Everyday math

Balloons Ramona bought 1818 balloons for a party. She wants to make 33 equal bunches. Find the number of balloons in each bunch, bb, by solving the equation 3b=183b=18. Teaching Connie’s kindergarten class has 2424 children. She wants them to get into 44 equal groups. Find the number of children in each group, gg, by solving the equation 4g=244g=24. 6 children Ticket price Daria paid {$36.25} for 55 children’s tickets at the ice skating rink. Find the price of each ticket, pp, by solving the equation 5p=36.255p=36.25. Unit price Nishant paid {$12.96} for a pack of 1212 juice bottles. Find the price of each bottle, bb, by solving the equation 12b=12.9612b=12.96. $1.08 Fuel economy Tania’s SUV gets half as many miles per gallon (mpg) as her husband’s hybrid car. The SUV gets 18 mpg\text{18 mpg}. Find the miles per gallons, mm, of the hybrid car, by solving the equation 12m=18\Large\frac{1}{2}\normalsize m=18. Fabric The drill team used 1414 yards of fabric to make flags for one-third of the members. Find how much fabric, ff, they would need to make flags for the whole team by solving the equation 13f=14\Large\frac{1}{3}\normalsize f=14. 42 yards
 

writing exercises

Frida started to solve the equation −3x=36-3x=36 by adding 33 to both sides. Explain why Frida’s method will result in the correct solution. Emiliano thinks x=40x=40 is the solution to the equation 12x=80\Large\frac{1}{2}\normalsize x=80. Explain why he is wrong. Answer will vary.

Solve Equations with Variables and Constants on Both Sides

Solve an Equation with Constants on Both Sides

In the following exercises, solve the equation for the variable. 6x−2=406x - 2=40 7x−8=347x - 8=34 6 11w+6=9311w+6=93 14y+7=9114y+7=91 6 3a+8=−463a+8=-46 4m+9=−234m+9=-23 −8 −50=7n−1-50=7n - 1 −47=6b+1-47=6b+1 −8 25=−9y+725=-9y+7 29=−8x−329=-8x - 3 −4 −12p−3=15-12p - 3=15 −14q−15=13-14\text{q}-15=13 −2 Solve an Equation with Variables on Both Sides In the following exercises, solve the equation for the variable. 8z=7z−78z=7z - 7 9k=8k−119k=8k - 11 −11 4x+36=10x4x+36=10x 6x+27=9x6x+27=9x 9 c=−3c−20c=-3c - 20 b=−4b−15b=-4b - 15 −3 5q=44−6q5q=44 - 6q 7z=39−6z7z=39 - 6z 3 3y+12=2y3y+\Large\frac{1}{2}\normalsize =2y 8x+34=7x8x+\Large\frac{3}{4}\normalsize =7x −3/4 −12a−8=−16a-12a - 8=-16a −15r−8=−11r-15r - 8=-11r 2 Solve an Equation with Variables and Constants on Both Sides In the following exercises, solve the equations for the variable. 6x−15=5x+36x - 15=5x+3 4x−17=3x+24x - 17=3x+2 19 26+8d=9d+1126+8d=9d+11 21+6f=7f+1421+6f=7f+14 7 3p−1=5p−333p - 1=5p - 33 8q−5=5q−208q - 5=5q - 20 −5 4a+5=−a−404a+5=-a - 40 9c+7=−2c−379c+7=-2c - 37 −4 8y−30=−2y+308y - 30=-2y+30 12x−17=−3x+1312x - 17=-3x+13 2 2z−4=23−z2\text{z}-4=23-\text{z} 3y−4=12−y3y - 4=12-y 4 54c−3=14c−16\Large\frac{5}{4}\normalsize c - 3=\Large\frac{1}{4}\normalsize c - 16 43m−7=13m−13\Large\frac{4}{3}\normalsize m - 7=\Large\frac{1}{3}\normalsize m - 13 6 8−25q=35q+68-\Large\frac{2}{5}\normalsize q=\Large\frac{3}{5}\normalsize q+6 11−14a=34a+411-\Large\frac{1}{4}\normalsize a=\Large\frac{3}{4}\normalsize a+4 7 43n+9=13n−9\Large\frac{4}{3}\normalsize n+9=\Large\frac{1}{3}\normalsize n - 9 54a+15=34a−5\Large\frac{5}{4}\normalsize a+15=\Large\frac{3}{4}\normalsize a - 5 −40 14y+7=34y−3\Large\frac{1}{4}\normalsize y+7=\Large\frac{3}{4}\normalsize y - 3 35p+2=45p−1\Large\frac{3}{5}\normalsize p+2=\Large\frac{4}{5}\normalsize p - 1 3 14n+8.25=9n+19.6014n+8.25=9n+19.60 13z+6.45=8z+23.7513z+6.45=8z+23.75 3.46 2.4w−100=0.8w+282.4w - 100=0.8w+28 2.7w−80=1.2w+102.7w - 80=1.2w+10 60 5.6r+13.1=3.5r+57.25.6r+13.1=3.5r+57.2 6.6x−18.9=3.4x+54.76.6x - 18.9=3.4x+54.7 23 Solve an Equation Using the General Strategy In the following exercises, solve the linear equation using the general strategy. 5(x+3)=755\left(x+3\right)=75 4(y+7)=644\left(y+7\right)=64 9 8=4(x−3)8=4\left(x - 3\right) 9=3(x−3)9=3\left(x - 3\right) 6 20(y−8)=−6020\left(y - 8\right)=-60 14(y−6)=−4214\left(y - 6\right)=-42 3 −4(2n+1)=16-4\left(2n+1\right)=16 −7(3n+4)=14-7\left(3n+4\right)=14 −2 3(10+5r)=03\left(10+5r\right)=0 8(3+3p)=08\left(3+3\text{p}\right)=0 −1 23(9c−3)=22\Large\frac{2}{3}\normalsize\left(9c - 3\right)=22 35(10x−5)=27\Large\frac{3}{5}\normalsize\left(10x - 5\right)=27 5 5(1.2u−4.8)=−125\left(1.2u - 4.8\right)=-12 4(2.5v−0.6)=7.64\left(2.5v - 0.6\right)=7.6 0.52 0.2(30n+50)=280.2\left(30n+50\right)=28 0.5(16m+34)=−150.5\left(16m+34\right)=-15 0.25 −(w−6)=24-\left(w - 6\right)=24 −(t−8)=17-\left(t - 8\right)=17 −9 9(3a+5)+9=549\left(3a+5\right)+9=54 8(6b−7)+23=638\left(6b - 7\right)+23=63 2 10+3(z+4)=1910+3\left(z+4\right)=19 13+2(m−4)=1713+2\left(m - 4\right)=17 6 7+5(4−q)=127+5\left(4-q\right)=12 −9+6(5−k)=12-9+6\left(5-k\right)=12 3/2 15−(3r+8)=2815-\left(3r+8\right)=28 18−(9r+7)=−1618-\left(9r+7\right)=-16 3 11−4(y−8)=4311 - 4\left(y - 8\right)=43 18−2(y−3)=3218 - 2\left(y - 3\right)=32 −4 9(p−1)=6(2p−1)9\left(p - 1\right)=6\left(2p - 1\right) 3(4n−1)−2=8n+33\left(4n - 1\right)-2=8n+3 2 9(2m−3)−8=4m+79\left(2m - 3\right)-8=4m+7 5(x−4)−4x=145\left(x - 4\right)-4x=14 34 8(x−4)−7x=148\left(x - 4\right)-7x=14 5+6(3s−5)=−3+2(8s−1)5+6\left(3s - 5\right)=-3+2\left(8s - 1\right) 10 −12+8(x−5)=−4+3(5x−2)-12+8\left(x - 5\right)=-4+3\left(5x - 2\right) 4(x−1)−8=6(3x−2)−74\left(x - 1\right)-8=6\left(3x - 2\right)-7 2 7(2x−5)=8(4x−1)−97\left(2x - 5\right)=8\left(4x - 1\right)-9

everyday math

Making a fence

Jovani has a fence around the rectangular garden in his backyard. The perimeter of the fence is 150150 feet. The length is 1515 feet more than the width. Find the width, ww, by solving the equation 150=2(w+15)+2w150=2\left(w+15\right)+2w. 30 feet

Concert tickets

At a school concert, the total value of tickets sold was {$1,506.} Student tickets sold for {$6} and adult tickets sold for {$9.} The number of adult tickets sold was 55 less than 33 times the number of student tickets. Find the number of student tickets sold, ss, by solving the equation 6s+9(3s−5)=15066s+9\left(3s - 5\right)=1506. Coins Rhonda has {$1.90} in nickels and dimes. The number of dimes is one less than twice the number of nickels. Find the number of nickels, nn, by solving the equation 0.05n+0.10(2n−1)=1.900.05n+0.10\left(2n - 1\right)=1.90. 8 nickels

Fencing

Micah has 7474 feet of fencing to make a rectangular dog pen in his yard. He wants the length to be 2525 feet more than the width. Find the length, LL, by solving the equation 2L+2(L−25)=742L+2\left(L - 25\right)=74.

 

writing exercises

When solving an equation with variables on both sides, why is it usually better to choose the side with the larger coefficient as the variable side? Answers will vary. Solve the equation 10x+14=−2x+3810x+14=-2x+38, explaining all the steps of your solution. What is the first step you take when solving the equation 3−7(y−4)=38?3 - 7\left(y - 4\right)=38? Explain why this is your first step. Answers will vary. Solve the equation 14(8x+20)=3x−4\Large\frac{1}{4}\normalsize\left(8x+20\right)=3x - 4 explaining all the steps of your solution as in the examples in this section. Using your own words, list the steps in the General Strategy for Solving Linear Equations. Answers will vary. Explain why you should simplify both sides of an equation as much as possible before collecting the variable terms to one side and the constant terms to the other side.

 

Solve Equations with Fraction or Decimal Coefficients

Solve equations with fraction coefficients

In the following exercises, solve the equation by clearing the fractions. 14x−12=−34\Large\frac{1}{4}\normalsize x-\Large\frac{1}{2}\normalsize =-\Large\frac{3}{4} x = −1 34x−12=14\Large\frac{3}{4}\normalsize x-\Large\frac{1}{2}\normalsize =\Large\frac{1}{4} 56y−23=−32\Large\frac{5}{6}\normalsize y-\Large\frac{2}{3}\normalsize =-\Large\frac{3}{2} y = −1 56y−13=−76\Large\frac{5}{6}\normalsize y-\Large\frac{1}{3}\normalsize =-\Large\frac{7}{6} 12a+38=34\Large\frac{1}{2}\normalsize a+\Large\frac{3}{8}\normalsize =\Large\frac{3}{4} a=34a=\Large\frac{3}{4} 58b+12=−34\Large\frac{5}{8}\normalsize b+\Large\frac{1}{2}\normalsize =-\Large\frac{3}{4} 2=13x−12x+23x2=\Large\frac{1}{3}\normalsize x-\Large\frac{1}{2}\normalsize x+\Large\frac{2}{3}\normalsize x x = 4 2=35x−13x+25x2=\Large\frac{3}{5}\normalsize x-\Large\frac{1}{3}\normalsize x+\Large\frac{2}{5}\normalsize x 14m−45m+12m=−1\Large\frac{1}{4}\normalsize m-\Large\frac{4}{5}\normalsize m+\Large\frac{1}{2}\normalsize m=-1 m = 20 56n−14n−12n=−2\Large\frac{5}{6}\normalsize n-\Large\frac{1}{4}\normalsize n-\Large\frac{1}{2}\normalsize n=-2 x+12=23x−12x+\Large\frac{1}{2}\normalsize =\Large\frac{2}{3}\normalsize x-\Large\frac{1}{2} x = −3 x+34=12x−54x+\Large\frac{3}{4}\normalsize =\Large\frac{1}{2}\normalsize x-\Large\frac{5}{4} 13w+54=w−14\Large\frac{1}{3}\normalsize w+\Large\frac{5}{4}\normalsize =w-\Large\frac{1}{4} w=94w=\Large\frac{9}{4} 32z+13=z−23\Large\frac{3}{2}\normalsize z+\Large\frac{1}{3}\normalsize =z-\Large\frac{2}{3} 12x−14=112x+16\Large\frac{1}{2}\normalsize x-\Large\frac{1}{4}\normalsize =\Large\frac{1}{12}\normalsize x+\Large\frac{1}{6} x = 1 12a−14=16a+112\Large\frac{1}{2}\normalsize a-\Large\frac{1}{4}\normalsize =\Large\frac{1}{6}\normalsize a+\Large\frac{1}{12} 13b+15=25b−35\Large\frac{1}{3}\normalsize b+\Large\frac{1}{5}\normalsize =\Large\frac{2}{5}\normalsize b-\Large\frac{3}{5} b = 12 13x+25=15x−25\Large\frac{1}{3}\normalsize x+\Large\frac{2}{5}\normalsize =\Large\frac{1}{5}\normalsize x-\Large\frac{2}{5} 1=16(12x−6)1=\Large\frac{1}{6}\normalsize\left(12x - 6\right) x = 1 1=15(15x−10)1=\Large\frac{1}{5}\normalsize\left(15x - 10\right) 14(p−7)=13(p+5)\Large\frac{1}{4}\normalsize\left(p - 7\right)=\Large\frac{1}{3}\normalsize\left(p+5\right) p = −41 15(q+3)=12(q−3)\Large\frac{1}{5}\normalsize\left(q+3\right)=\Large\frac{1}{2}\normalsize\left(q - 3\right) 12(x+4)=34\Large\frac{1}{2}\normalsize\left(x+4\right)=\Large\frac{3}{4} x=−52x=-\Large\frac{5}{2} 13(x+5)=56\Large\frac{1}{3}\normalsize\left(x+5\right)=\Large\frac{5}{6}

Solve Equations with Decimal Coefficients

In the following exercises, solve the equation by clearing the decimals. 0.6y+3=90.6y+3=9 y = 10 0.4y−4=20.4y - 4=2 3.6j−2=5.23.6j - 2=5.2 j = 2 2.1k+3=7.22.1k+3=7.2 0.4x+0.6=0.5x−1.20.4x+0.6=0.5x - 1.2 x = 18 0.7x+0.4=0.6x+2.40.7x+0.4=0.6x+2.4 0.23x+1.47=0.37x−1.050.23x+1.47=0.37x - 1.05 x = 18 0.48x+1.56=0.58x−0.640.48x+1.56=0.58x - 0.64 0.9x−1.25=0.75x+1.750.9x - 1.25=0.75x+1.75 x = 20 1.2x−0.91=0.8x+2.291.2x - 0.91=0.8x+2.29 0.05n+0.10(n+8)=2.150.05n+0.10\left(n+8\right)=2.15 n = 9 0.05n+0.10(n+7)=3.550.05n+0.10\left(n+7\right)=3.55 0.10d+0.25(d+5)=4.050.10d+0.25\left(d+5\right)=4.05 d = 8 0.10d+0.25(d+7)=5.250.10d+0.25\left(d+7\right)=5.25 0.05(q−5)+0.25q=3.050.05\left(q - 5\right)+0.25q=3.05 q = 11 0.05(q−8)+0.25q=4.100.05\left(q - 8\right)+0.25q=4.10

Everyday math

Coins Taylor has {$2.00} in dimes and pennies. The number of pennies is 22 more than the number of dimes. Solve the equation 0.10d+0.01(d+2)=20.10d+0.01\left(d+2\right)=2 for dd, the number of dimes. d = 18 Stamps Travis bought {$9.45} worth of 49-cent\text{49-cent} stamps and 21-cent\text{21-cent} stamps. The number of 21-cent\text{21-cent} stamps was 55 less than the number of 49-cent\text{49-cent} stamps. Solve the equation 0.49s+0.21(s−5)=9.450.49s+0.21\left(s - 5\right)=9.45 for ss, to find the number of 49-cent\text{49-cent} stamps Travis bought.
 

writing exercises

Explain how to find the least common denominator of 38,16,and23\Large\frac{3}{8}\normalsize ,\Large\frac{1}{6}\normalsize ,\text{and}\Large\frac{2}{3}. Answers will vary. If an equation has several fractions, how does multiplying both sides by the LCD make it easier to solve? If an equation has fractions only on one side, why do you have to multiply both sides of the equation by the LCD? Answers will vary. In the equation 0.35x+2.1=3.850.35x+2.1=3.85, what is the LCD? How do you know?

 

Chapter Review Exercises

Solve Equations using the Subtraction and Addition Properties of Equality

In the following exercises, determine whether the given number is a solution to the equation. x+16=31,x=15x+16=31,x=15 yes w−8=5,w=3w - 8=5,w=3 −9n=45,n=54-9n=45,n=54 no 4a=72,a=184a=72,a=18 In the following exercises, solve the equation using the Subtraction Property of Equality. x+7=19x+7=19 12 y+2=−6y+2=-6 a+13=53a+\Large\frac{1}{3}\normalsize =\Large\frac{5}{3} a=43a=\Large\frac{4}{3} n+3.6=5.1n+3.6=5.1 In the following exercises, solve the equation using the Addition Property of Equality. u−7=10u - 7=10 u = 17 x−9=−4x - 9=-4 c−311=911c-\Large\frac{3}{11}\normalsize =\Large\frac{9}{11} c=1211c=\Large\frac{12}{11} p−4.8=14p - 4.8=14 In the following exercises, solve the equation. n−12=32n - 12=32 n = 44 y+16=−9y+16=-9 f+23=4f+\Large\frac{2}{3}\normalsize =4 f=103f=\Large\frac{10}{3} d−3.9=8.2d - 3.9=8.2 y+8−15=−3y+8 - 15=-3 y = 4 7x+10−6x+3=57x+10 - 6x+3=5 6(n−1)−5n=−146\left(n - 1\right)-5n=-14 n = −8 8(3p+5)−23(p−1)=358\left(3p+5\right)-23\left(p - 1\right)=35 In the following exercises, translate each English sentence into an algebraic equation and then solve it. The sum of −6-6 and mm is 2525. −6 + m = 25; m = 31 Four less than nn is 1313. In the following exercises, translate into an algebraic equation and solve. Rochelle’s daughter is 1111 years old. Her son is 33 years younger. How old is her son? s = 11 − 3; 8 years old Tan weighs 146146 pounds. Minh weighs 1515 pounds more than Tan. How much does Minh weigh? Peter paid {$9.75} to go to the movies, which was {$46.25} less than he paid to go to a concert. How much did he pay for the concert? c − 46.25 = 9.75; $56.00 Elissa earned {$152.84} this week, which was {$21.65} more than she earned last week. How much did she earn last week?

 

Solve Equations using the Division and Multiplication Properties of Equality

In the following exercises, solve each equation using the Division Property of Equality. 8x=728x=72 x = 9 13a=−6513a=-65 0.25p=5.250.25p=5.25 p = 21 −y=4-y=4 In the following exercises, solve each equation using the Multiplication Property of Equality. n6=18\Large\frac{n}{6}\normalsize =18 n = 108 y−10=30\Large\frac{y}{-10}\normalsize =30 36=34x36=\Large\frac{3}{4}\normalsize x x = 48 58u=1516\Large\frac{5}{8}\normalsize u=\Large\frac{15}{16} In the following exercises, solve each equation. −18m=−72-18m=-72 m = 4 c9=36\Large\frac{c}{9}\normalsize =36 0.45x=6.750.45x=6.75 x = 15 1112=23y\Large\frac{11}{12}\normalsize =\Large\frac{2}{3}\normalsize y 5r−3r+9r=35−25r - 3r+9r=35 - 2 r = 3 24x+8x−11x=−7−1424x+8x - 11x=-7 - 14

 

Solve Equations with Variables and Constants on Both Sides

In the following exercises, solve the equations with constants on both sides. 8p+7=478p+7=47 p = 5 10w−5=6510w - 5=65 3x+19=−473x+19=-47 x = −22 32=−4−9n32=-4 - 9n In the following exercises, solve the equations with variables on both sides. 7y=6y−137y=6y - 13 y = −13 5a+21=2a5a+21=2a k=−6k−35k=-6k - 35 k = −5 4x−38=3x4x-\Large\frac{3}{8}\normalsize =3x In the following exercises, solve the equations with constants and variables on both sides. 12x−9=3x+4512x - 9=3x+45 x = 6 5n−20=−7n−805n - 20=-7n - 80 4u+16=−19−u4u+16=-19-u u = −7 58c−4=38c+4\Large\frac{5}{8}\normalsize c - 4=\Large\frac{3}{8}\normalsize c+4 In the following exercises, solve each linear equation using the general strategy. 6(x+6)=246\left(x+6\right)=24 x = −2 9(2p−5)=729\left(2p - 5\right)=72 −(s+4)=18-\left(s+4\right)=18 s = −22 8+3(n−9)=178+3\left(n - 9\right)=17 23−3(y−7)=823 - 3\left(y - 7\right)=8 y = 12 13(6m+21)=m−7\Large\frac{1}{3}\normalsize\left(6m+21\right)=m - 7 8(r−2)=6(r+10)8\left(r - 2\right)=6\left(r+10\right) r = 38 5+7(2−5x)=2(9x+1)−(13x−57)5+7\left(2 - 5x\right)=2\left(9x+1\right)-\left(13x - 57\right) 4(3.5y+0.25)=3654\left(3.5y+0.25\right)=365 y = 26 0.25(q−8)=0.1(q+7)0.25\left(q - 8\right)=0.1\left(q+7\right)

 

Solve Equations with Fraction or Decimal Coefficients

In the following exercises, solve each equation by clearing the fractions. 25n−110=710\Large\frac{2}{5}\normalsize n-\Large\frac{1}{10}\normalsize =\Large\frac{7}{10} n = 2 13x+15x=8\Large\frac{1}{3}\normalsize x+\Large\frac{1}{5}\normalsize x=8 34a−13=12a+56\Large\frac{3}{4}\normalsize a-\Large\frac{1}{3}\normalsize =\Large\frac{1}{2}\normalsize a+\Large\frac{5}{6} a=143a=\Large\frac{14}{3} 12(k+3)=13(k+16)\Large\frac{1}{2}\normalsize\left(k+3\right)=\Large\frac{1}{3}\normalsize\left(k+16\right) In the following exercises, solve each equation by clearing the decimals. 0.8x−0.3=0.7x+0.20.8x - 0.3=0.7x+0.2 x = 5 0.36u+2.55=0.41u+6.80.36u+2.55=0.41u+6.8 0.6p−1.9=0.78p+1.70.6p - 1.9=0.78p+1.7 p = −20 0.10d+0.05(d−4)=2.050.10d+0.05\left(d - 4\right)=2.05

 

Chapter Practice Test

Determine whether each number is a solution to the equation. 3x+5=233x+5=23. ⓐ 66 ⓑ 235\Large\frac{23}{5} ⓐ yes ⓑ no In the following exercises, solve each equation. n−18=31n - 18=31 9c=1449c=144 c = 16 4y−8=164y - 8=16 −8x−15+9x−1=−21-8x - 15+9x - 1=-21 x = −5 −15a=120-15a=120 23x=6\Large\frac{2}{3}\normalsize x=6 x = 9 x+3.8=8.2x+3.8=8.2 10y=−5y+6010y=-5y+60 y = 4 8n+2=6n+128n+2=6n+12 9m−2−4m+m=42−89m - 2 - 4m+m=42 - 8 m = 6 −5(2x+1)=45-5\left(2x+1\right)=45 −(d+9)=23-\left(d+9\right)=23 d = −32 13(6m+21)=m−7\Large\frac{1}{3}\normalsize\left(6m+21\right)=m - 7 2(6x+5)−8=−222\left(6x+5\right)-8=-22 x = −2 8(3a+5)−7(4a−3)=20−3a8\left(3a+5\right)-7\left(4a - 3\right)=20 - 3a 14p+13=12\Large\frac{1}{4}\normalsize p+\Large\frac{1}{3}\normalsize =\Large\frac{1}{2} p=23p=\Large\frac{2}{3} 0.1d+0.25(d+8)=4.10.1d+0.25\left(d+8\right)=4.1 Translate and solve: The difference of twice xx and 44 is 1616. 2x − 4 = 16; x = 10 Samuel paid {$25.82} for gas this week, which was {$3.47} less than he paid last week. How much did he pay last week?

Determine Whether a Decimal is a Solution of an Equation In the following exercises, determine whether each number is a solution of the given equation.

x−0.8=2.3x - 0.8=2.3

ⓐ x=2x=2 ⓑ x=−1.5x=-1.5 ⓒ x=3.1x=3.1

ⓐ no ⓑ no ⓒ yes

y+0.6=−3.4y+0.6=-3.4

ⓐ y=−4y=-4 ⓑ y=−2.8y=-2.8 ⓒ y=2.6y=2.6

h1.5=−4.3\Large\frac{h}{1.5}\normalsize =-4.3

ⓐ h=6.45h=6.45 ⓑ h=−6.45h=-6.45 ⓒ h=−2.1h=-2.1

ⓐ no ⓑ yes ⓒ no

0.75k=−3.60.75k=-3.6

ⓐ k=−0.48k=-0.48 ⓑ k=−4.8k=-4.8 ⓒ k=−2.7k=-2.7

Solve Equations with Decimals

In the following exercises, solve the equation.

y+2.9=5.7y+2.9=5.7

y = 2.8

m+4.6=6.5m+4.6=6.5

f+3.45=2.6f+3.45=2.6

f = −0.85

h+4.37=3.5h+4.37=3.5

a+6.2=−1.7a+6.2=-1.7

a = −7.9

b+5.8=−2.3b+5.8=-2.3

c+1.15=−3.5c+1.15=-3.5

c = −4.65

d+2.35=−4.8d+2.35=-4.8

n−2.6=1.8n - 2.6=1.8

n = 4.4

p−3.6=1.7p - 3.6=1.7

x−0.4=−3.9x - 0.4=-3.9

x = −3.5

y−0.6=−4.5y - 0.6=-4.5

j−1.82=−6.5j - 1.82=-6.5

j = −4.68

k−3.19=−4.6k - 3.19=-4.6

m−0.25=−1.67m - 0.25=-1.67

m = −1.42

q−0.47=−1.53q - 0.47=-1.53

0.5x=3.50.5x=3.5

x = 7

0.4p=9.20.4p=9.2

−1.7c=8.5-1.7c=8.5

c = −5

−2.9x=5.8-2.9x=5.8

−1.4p=−4.2-1.4p=-4.2

p = 3

−2.8m=−8.4-2.8m=-8.4

−120=1.5q-120=1.5q

q = −80

−75=1.5y-75=1.5y

0.24x=4.80.24x=4.8

x = 20

0.18n=5.40.18n=5.4

−3.4z=−9.18-3.4z=-9.18

z = 2.7

−2.7u=−9.72-2.7u=-9.72

a0.4=−20\Large\frac{a}{0.4}\normalsize =-20

a = −8

b0.3=−9\Large\frac{b}{0.3}\normalsize =-9

x0.7=−0.4\Large\frac{x}{0.7}\normalsize =-0.4

x = −0.28

y0.8=−0.7\Large\frac{y}{0.8}\normalsize =-0.7

p−5=−1.65\Large\frac{p}{-5}\normalsize =-1.65

p = 8.25

q−4=−5.92\Large\frac{q}{-4}\normalsize =-5.92

r−1.2=−6\Large\frac{r}{-1.2}\normalsize =-6

r = 7.2

s−1.5=−3\Large\frac{s}{-1.5}\normalsize =-3

Mixed Practice

In the following exercises, solve the equation. Then check your solution.

x−5=−11x - 5=-11

x = −6

−25=x+34-\Large\frac{2}{5}\normalsize =x+\Large\frac{3}{4}

p+8=−2p+8=-2

p = −10

p+23=112p+\Large\frac{2}{3}\normalsize =\Large\frac{1}{12}

−4.2m=−33.6-4.2m=-33.6

m = 8

q+9.5=−14q+9.5=-14

q+56=112q+\Large\frac{5}{6}\normalsize =\Large\frac{1}{12}

q=−34q=-\Large\frac{3}{4}

8.615=−d\Large\frac{8.6}{15}\normalsize =-d

78m=110\Large\frac{7}{8}\normalsize m=\Large\frac{1}{10}

m=435m=\Large\frac{4}{35}

j−6.2=−3\Large\frac{j}{-6.2}\normalsize =-3

−23=y+38-\Large\frac{2}{3}\normalsize =y+\Large\frac{3}{8}

y=−2524y=-\Large\frac{25}{24}

s−1.75=−3.2s - 1.75=-3.2

1120=−f\Large\frac{11}{20}\normalsize =-f

f=−1120f=-\Large\frac{11}{20}

−3.6b=2.52-3.6b=2.52

−4.2a=3.36-4.2a=3.36

a = −0.8

−9.1n=−63.7-9.1n=-63.7

r−1.25=−2.7r - 1.25=-2.7

r = −1.45

14n=710\Large\frac{1}{4}\normalsize n=\Large\frac{7}{10}

h−3=−8\Large\frac{h}{-3}\normalsize =-8

h = 24

y−7.82=−16y - 7.82=-16

Translate to an Equation and Solve

In the following exercises, translate and solve.

The difference of nn and 1.91.9 is 3.43.4.

n−1.9=3.4;5.3n - 1.9=3.4;5.3

The difference nn and 1.51.5 is 0.80.8.

The product of −6.2-6.2 and xx is −4.96-4.96.

−6.2x = −4.96; 0.8

The product of −4.6-4.6 and xx is −3.22-3.22.

The quotient of yy and −1.7-1.7 is −5-5.

y−1.7=−5;8.5\Large\frac{y}{-1.7}\normalsize =-5;8.5

The quotient of zz and −3.6-3.6 is 33.

The sum of nn and −7.3-7.3 is 2.42.4.

n + (−7.3) = 2.4; 9.7

The sum of nn and −5.1-5.1 is 3.83.8.

Everyday math

Shawn bought a pair of shoes on sale for $78 . Solve the equation 0.75p=780.75p=78 to find the original price of the shoes, pp.

$104

Mary bought a new refrigerator. The total price including sales tax was {$1,350}. Find the retail price, rr, of the refrigerator before tax by solving the equation 1.08r=1,3501.08r=1,350.

 

writing exercises

Think about solving the equation 1.2y=601.2y=60, but do not actually solve it. Do you think the solution should be greater than 6060 or less than 60?60? Explain your reasoning. Then solve the equation to see if your thinking was correct.

Answers will vary.

Think about solving the equation 0.8x=2000.8x=200, but do not actually solve it. Do you think the solution should be greater than 200200 or less than 200?200? Explain your reasoning. Then solve the equation to see if your thinking was correct.

 

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