Worked-out Problems

Chapter 3 continued
41. c 12 23
c 12 12 23 12
c 11
Check: c 12 23
11 12 23
23 23 ✓
42. b 14 91
b 14 14 91 14
b 77
Check: b 14 91
77 14 91
91 91 ✓
43. x 17 45
x 17 17 45 17
x 28
Check: x 17 45
28 17 45
45 45 ✓
44. d 22 43
d 22 22 43 22
d 21
Check: d 22 43
21 22 43
43 43 ✓
3.1 Standardized Test Practice (p. 124)
45. B; 15y 63 57
15y 63 63 57 63
15y 120
1 5y
1 20
15
15
y 8
46. Let x the amount of each monthly payment. Write a
verbal model.
Cost of
Number of Cost of
Down
video monthly p monthly
payment
game
payments payment
150 25 5x
Subtract 25 from each side.
150 25 25 5x 25
125 5x
Divide each side by 5.
12 5
5 x
5 5
25 x
Each monthly payment is $25.
Lesson 3.2
3.2 Checkpoint (p. 126)
1. 3n 40 2n 15
5n 40 15
5n 40 40 15 40
5n 55
5 n
5 5
5 5
n 11
Check: 3n 40 2n 15
3(11) 40 2(11) 15
15 15 ✓
2. 2(s 1) 6
2s 2 6
2s 2 2 6 2
2s 8
2 s
8 2 2
s 4
Check: 2(s 1) 6
2(4 1) 6
6 6 ✓
3. 13 2y 3(y 4)
13 2y 3y 12
13 y 12
13 12 y 12 12
25 y
25 y
1 1
25 y
Check: 13 2y 3(y 4)
13 2(25) 3[(25) 4]
13 13 ✓
3.2 Guided Practice (p. 127)
1. Use the distributive property to rewrite 6(x 1) 12 as
6x 6 12.
2. In the equation 3x 5 2x 8 12, the like terms
are 3x and 2x, and 5 and 8.
3. 4 x 7 10
x 11 10
x 11 11 10 11
x 1
Check: 4 x 7 10
4 (1) 7 10
10 10 ✓
74 Pre-Algebra
Chapter 3 Worked-Out Solution Key
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