Worked-out Problems

Chapter 3 continued
3.2 Standardized Test Practice (p. 129)
55. D; 3(2x 1) 21
6x 3 21
6x 3 3 21 3
6x 24
6
x
6
24
6
x 4
56. Let w the width of the rectangle.
So, l 2w 5.
P 2l 2w
38 2(2w 5) 2w
38 4w 10 2w
38 6w 10
38 10 6w 10 10
48 6w
4 8
6 w
6 6
8 w
So, the width of the rectangle is 8 feet, and the length is
2(8) 5 16 5 11 feet.
Brain Game (p. 129)
A. 10x 7 17
10x 7 7 17 7
10x 10
1 0x
10
1 0
1
0
x 1
2(7x 6) 40
14x 12 40
14x 12 12 40 12
14x 28
1 4x
14
2 8
1
4
x 2
(x 11) 10
x 11 10
x 11 11 10 11
x 1
x
1
1 1
x 1
––CONTINUED––
Brain Game ––CONTINUED––
B. 8x 15 47
8x 15 15 47 15
8x 32
8 x
32
8 8
x 4
6(2x 1) 90
12x 6 90
12x 6 6 90 6
12x 96
1 2x
9 6
12
12
x 8
7x 4x 24
3x 24
3
x
3
24
3
x 8
C. 5x 4x 6
x 6
x
6
1 1
x 6
7x (12) 61
7x (12) (12) 61 (12)
7x 49
7 x
4 9
7 7
x 7
7(x 2) 63
7x 14 63
7x 14 14 63 14
7x 49
7 x
4 9
7 7
x 7
D. 2(6x 7) 50
12x 14 50
12x 14 14 50 14
12x 36
1 2x
3 6
12
12
x 3
––CONTINUED––
80 Pre-Algebra
Chapter 3 Worked-Out Solution Key
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