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5.4 Solve Equations with Decimals

Isolating a variable when coefficients and constants carry decimal points, checking a decimal solution, and translating sentences into those equations.

Prealgebra 2e, 5.4 Solve Equations with Decimals

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57 exercises

5.4 Exercise 1

Before you get started, take this readiness quiz.

Evaluate x+23whenx=−14.x + \frac{2}{3} \text{when} x = - \frac{1}{4} .
If you missed this problem, review the reference.

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5.4 Exercise 2

Evaluate 15−y15 - y when y=−5.y = −5 .
If you missed this problem, review the reference.

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5.4 Exercise 3

Solve n−7=42.\frac{n}{- 7} = 42 .
If you missed this problem, review the reference.

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5.4 Exercise 5

Determine whether each value is a solution of the given equation.

x−0.6=1.3:x - 0.6 = 1.3 :ⓐ x=0.7x = 0.7ⓑ x=1.9x = 1.9ⓒ x=−0.7x = −0.7

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5.4 Exercise 6

Determine whether each value is a solution of the given equation.

y−0.4=1.7:y - 0.4 = 1.7 :ⓐ y=2.1y = 2.1ⓑ y=1.3y = 1.3ⓒ −1.3−1.3

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5.4 Exercise 8

Solve: y+2.7=−5.3.y + 2.7 = −5.3 .

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5.4 Exercise 9

Solve: y+3.6=−4.8.y + 3.6 = −4.8 .

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5.4 Exercise 11

Solve: a−3.93=−2.86.a - 3.93 = −2.86 .

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5.4 Exercise 12

Solve: n−3.47=−2.64.n - 3.47 = −2.64 .

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5.4 Exercise 14

Solve: −8.4=0.7b.−8.4 = 0.7 b .

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5.4 Exercise 15

Solve: −5.6=0.7c.−5.6 = 0.7 c .

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5.4 Exercise 17

Solve: c−2.6=−4.5.\frac{c}{−2.6} = −4.5 .

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5.4 Exercise 18

Solve: b−1.2=−5.4.\frac{b}{−1.2} = −5.4 .

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5.4 Exercise 20

Translate and solve: The difference of yy and 4.94.9 is 2.8.2.8 .

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5.4 Exercise 21

Translate and solve: The difference of zz and 5.75.7 is 3.4.3.4 .

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5.4 Exercise 23

Translate and solve: The product of −4.3−4.3 and xx is 12.04.12.04 .

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5.4 Exercise 24

Translate and solve: The product of −3.1−3.1 and mm is 26.66.26.66 .

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5.4 Exercise 26

Translate and solve: The quotient of qq and −3.4−3.4 is 4.5.4.5 .

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5.4 Exercise 27

Translate and solve: The quotient of rr and −2.6−2.6 is 2.5.2.5 .

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5.4 Exercise 29

Translate and solve: The sum of jj and 3.83.8 is 2.6.2.6 .

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5.4 Exercise 30

Translate and solve: The sum of kk and 4.74.7 is 0.3.0.3 .

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5.4 Exercise 31

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

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5.4 Exercise 33

Determine whether each number is a solution of the given equation.

h1.5=−4.3\frac{h}{1.5} = −4.3
ⓐ h=6.45h = 6.45ⓑ h=−6.45h = −6.45ⓒ h=−2.1h = −2.1

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5.4 Exercise 35

Solve the equation.

y+2.9=5.7y + 2.9 = 5.7

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5.4 Exercise 37

Solve the equation.

f+3.45=2.6f + 3.45 = 2.6

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5.4 Exercise 39

Solve the equation.

a+6.2=−1.7a + 6.2 = −1.7

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5.4 Exercise 41

Solve the equation.

c+1.15=−3.5c + 1.15 = −3.5

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5.4 Exercise 43

Solve the equation.

n−2.6=1.8n - 2.6 = 1.8

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5.4 Exercise 45

Solve the equation.

x−0.4=−3.9x - 0.4 = −3.9

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5.4 Exercise 47

Solve the equation.

j−1.82=−6.5j - 1.82 = −6.5

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5.4 Exercise 49

Solve the equation.

m−0.25=−1.67m - 0.25 = −1.67

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5.4 Exercise 51

Solve the equation.

0.5x=3.50.5 x = 3.5

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5.4 Exercise 53

Solve the equation.

−1.7c=8.5−1.7 c = 8.5

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5.4 Exercise 55

Solve the equation.

−1.4p=−4.2−1.4 p = −4.2

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5.4 Exercise 57

Solve the equation.

−120=1.5q−120 = 1.5 q

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5.4 Exercise 59

Solve the equation.

0.24x=4.80.24 x = 4.8

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5.4 Exercise 61

Solve the equation.

−3.4z=−9.18−3.4 z = −9.18

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5.4 Exercise 63

Solve the equation.

a0.4=−20\frac{a}{0.4} = −20

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5.4 Exercise 65

Solve the equation.

x0.7=−0.4\frac{x}{0.7} = −0.4

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5.4 Exercise 67

Solve the equation.

p−5=−1.65\frac{p}{- 5} = −1.65

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5.4 Exercise 69

Solve the equation.

r−1.2=−6\frac{r}{- 1.2} = −6

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5.4 Exercise 71

Solve the equation. Then check your solution.

x−5=−11x - 5 = −11

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5.4 Exercise 73

Solve the equation. Then check your solution.

p+8=−2p + 8 = −2

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5.4 Exercise 75

Solve the equation. Then check your solution.

−4.2m=−33.6−4.2 m = −33.6

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5.4 Exercise 77

Solve the equation. Then check your solution.

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

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5.4 Exercise 79

Solve the equation. Then check your solution.

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

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5.4 Exercise 81

Solve the equation. Then check your solution.

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

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5.4 Exercise 83

Solve the equation. Then check your solution.

1120=−f\frac{11}{20} = - f

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5.4 Exercise 85

Solve the equation. Then check your solution.

−4.2a=3.36−4.2 a = 3.36

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5.4 Exercise 87

Solve the equation. Then check your solution.

r−1.25=−2.7r - 1.25 = −2.7

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5.4 Exercise 89

Solve the equation. Then check your solution.

h−3=−8\frac{h}{- 3} = −8

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5.4 Exercise 91

Translate and solve.

The difference of nn and 1.91.9 is 3.4.3.4 .

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5.4 Exercise 93

Translate and solve.

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

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5.4 Exercise 95

Translate and solve.

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

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5.4 Exercise 97

Translate and solve.

The sum of nn and −7.3−7.3 is 2.4.2.4.

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5.4 Exercise 99

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

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5.4 Exercise 101

Think about solving the equation 1.2y=60,1.2 y = 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.

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Adapted from Prealgebra 2e © 2020 Rice University. Licensed under CC BY 4.0. Source: Prealgebra 2e. Imported at revision 77a933c.