Prealgebra 2e

# Chapter 8

Prealgebra 2eChapter 8

### Be Prepared

8.1

$28 28$

8.2

$x − 5 x − 5$

8.3

yes

8.4

$1 1$

8.5

$− 8 3 − 8 3$

8.6

$− 25 − 25$

8.7

$4 y 4 y$

8.8

$4 4$

8.9

$− 21 − 21$

8.10

$3 3$

8.11

$12 12$

8.12

$478 478$

### Try It

8.1

no

8.2

no

8.3

x = −16

8.4

x = −20

8.5

n = −1

8.6

x = −4

8.7

$p = 7 6 p = 7 6$

8.8

$q = 2 3 q = 2 3$

8.9

b = 6.4

8.10

c = 14

8.11

y = 15

8.12

z = 2

8.13

p = 5

8.14

q = −16

8.15

h = −1

8.16

x = 1

8.17

x + 11 = 41; x = 30

8.18

y − 12 = 51; y = 63

8.19

4x − 3x = 14; x = 14

8.20

7a − 6a = −8; a = −8

8.21

a + 6 = 13; Athena weighs 7 pounds.

8.22

26 + h = 68; Henry has 42 books.

8.23

19,875 = s − 1025; the sticker price is $20,900. 8.24 7.75 = n − 3.25; the price at night is$11.00.

8.25

y = −16

8.26

z = −13

8.27

b = 144

8.28

c = 128

8.29

k = −8

8.30

g = −3

8.31

n = 35

8.32

y = 18

8.33

x = 2

8.34

n = −5

8.35

c = −3

8.36

$x = − 4 7 x = − 4 7$

8.37

n = −6

8.38

n = −5

8.39

x = −4

8.40

a = −8

8.41

y = 5

8.42

m = 9

8.43

n = 10

8.44

c = 1

8.45

p = −7

8.46

m = −3

8.47

j = 2

8.48

h = 1

8.49

x = −1

8.50

y = 4

8.51

q = 1

8.52

n = 1

8.53

a = −5

8.54

k = −6

8.55

x = 10

8.56

y = −3

8.57

x = −5

8.58

y = −5

8.59

x = 4

8.60

y = 1

8.61

y = −6

8.62

z = 8

8.63

a = 2

8.64

n = 2

8.65

$j = 5 3 j = 5 3$

8.66

$k = 5 2 k = 5 2$

8.67

p = −2

8.68

q = −8

8.69

u = 2

8.70

x = 4

8.71

n = 1

8.72

m = −1

8.73

$x = 1 2 x = 1 2$

8.74

y = 3

8.75

v = 40

8.76

u = −12

8.77

a = −2

8.78

c = −2

8.79

p = −4

8.80

q = 2

8.81

n = 2

8.82

m = −1

8.83

x = 20

8.84

x = 10

8.85

h = 12

8.86

k = −1

8.87

n = 9

8.88

d = 16

### Section 8.1 Exercises

1.

yes

3.

no

5.

x = 5

7.

$b = 1 2 b = 1 2$

9.

p = −11.7

11.

a = 10

13.

$x = 7 3 x = 7 3$

15.

y = 13.8

17.

x = −27

19.

$q = − 1 4 q = − 1 4$

21.

$y = 27 20 y = 27 20$

23.

m = 17

25.

x = 8

27.

n = −20

29.

y = 2

31.

w = −1.7

33.

x = −2

35.

m = −4

37.

k = 6

39.

c = −41

41.

y = 28

43.

x + (−5) = 33; x = 38

45.

y − 3 = −19; y = −16

47.

p + 8 = 52; p = 44

49.

5c − 4c = 60; c = 60

51.

$f − 1 3 = 1 12 ; f = 5 12 f − 1 3 = 1 12 ; f = 5 12$

53.

−9m + 10m = −25; m = −25

55.

Let p equal the number of pages read in the Psychology book. 41 + p = 54. Jeff read 13 pages in his Psychology book.

57.

Let d equal the daughter’s age. d = 12 − 5. Eva’s daughter’s age is 7 years old.

59.

21 pounds

61.

100.5 degrees

63.

109.

42 yards

111.

### Section 8.3 Exercises

113.

x = 6

115.

y = 6

117.

m = −8

119.

b = −8

121.

x = −4

123.

q = −2

125.

k = −11

127.

x = 9

129.

b = −3

131.

z = 3

133.

$x = − 3 4 x = − 3 4$

135.

r = −2

137.

x = 19

139.

f = 7

141.

q = −5

143.

c = −4

145.

x = 2

147.

y = 4

149.

m = −6

151.

a = 7

153.

a = −40

155.

p = 15

157.

z = 3.46

159.

w = 60

161.

x = 23

163.

y = 9

165.

x = 6

167.

y = 3

169.

n = −2

171.

p = −1

173.

x = 5

175.

v = 1

177.

m = 0.25

179.

t = −9

181.

b = 2

183.

m = 6

185.

$k = 3 2 k = 3 2$

187.

r = 3

189.

y = −4

191.

n = 2

193.

x = 34

195.

s = 10

197.

$x = 1 2 x = 1 2$

199.

30 feet

201.

8 nickels

203.

205.

207.

### Section 8.4 Exercises

209.

x = −1

211.

y = −1

213.

$a = 3 4 a = 3 4$

215.

x = 4

217.

m = 20

219.

x = −3

221.

$w = 9 4 w = 9 4$

223.

x = 1

225.

b = 12

227.

x = 1

229.

p = −41

231.

$x = − 5 2 x = − 5 2$

233.

y = 10

235.

j = 2

237.

x = 18

239.

x = 18

241.

x = 20

243.

n = 9

245.

d = 8

247.

q = 11

249.

d = 18

251.

253.

### Review Exercises

255.

yes

257.

no

259.

12

261.

$a = 4 3 a = 4 3$

263.

u = 17

265.

$c = 12 11 c = 12 11$

267.

n = 44

269.

$f = 10 3 f = 10 3$

271.

y = 4

273.

n = −8

275.

−6 + m = 25; m = 31

277.

s = 11 − 3; 8 years old

279.

c − 46.25 = 9.75; \$56.00

281.

x = 9

283.

p = 21

285.

n = 108

287.

x = 48

289.

m = 4

291.

x = 15

293.

r = 3

295.

p = 5

297.

x = −22

299.

y = −13

301.

k = −5

303.

x = 6

305.

u = −7

307.

x = −2

309.

s = −22

311.

y = 12

313.

r = 38

315.

y = 26

317.

n = 2

319.

$a = 14 3 a = 14 3$

321.

x = 5

323.

p = −20

### Practice Test

325.
1. yes
2. no
327.

c = 16

329.

x = −5

331.

x = 9

333.

y = 4

335.

m = 6

337.

d = −32

339.

x = −2

341.

$p = 2 3 p = 2 3$

343.

2x − 4 = 16; x = 10

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