Answer: (10) C (11) D (12) B (13) D (14) C (15) A
<u>Step-by-step explanation:</u>
10) 9x - 1 > 9 - x or 7x - 4 ≥ 4 + 9x
<u> +x </u> <u> +x </u> <u> -9x </u> <u> -9x</u>
10x - 1 > 9 -2x - 4 ≥ 4
<u> +1 </u> <u>+1 </u> <u> +4 </u> <u>+4 </u>
10x > 10 -2x ≥ 8
<u> ÷10 </u> <u>÷10 </u> <u> ÷ -2 </u> ↓ <u>÷ -2 </u>
x > 1 or x ≤ -4
11) 7 + 4x < 4x - 7 or -x + 6 > x + 6
<u> -4x </u> <u> -4x </u> <u> -x </u> <u>-x </u>
7 < -7 -2x + 6 > 6
FALSE <u> -6 </u> <u> -6 </u>
-2x > 0
<u> ÷ -2 </u> ↓ <u> ÷ -2 </u>
x < 0
12) |x + 1| = 10
x + 1 = 10 or x + 1 = -10
<u> -1 </u> <u> -1 </u> <u> -1 </u> <u> -1 </u>
x = 9 or x = -11
x = {9, -11}
13) 3 - 7 | -1 + 2x| = -116
<u> -3 </u> <u> -3 </u>
- 7 | -1 + 2x| = -119
<u> ÷ -7 </u> <u> ÷ -7 </u>
| -1 + 2x| = 17
-1 + 2x = 17 or -1 + 2x = -17
<u> +1 </u> <u> +1 </u> <u>+1 </u> <u> +1 </u>
2x = 18 2x = -16
<u> ÷2 </u> <u>÷2 </u> <u> ÷2 </u> <u> ÷2 </u>
x = 9 or x = -8
x = {9, -8}
14) 8 - | 2n - 8 | = 0
<u> -8 </u> <u> -8 </u>
- | 2n - 8 | = -8
<u> ÷ -1 </u> <u> ÷ -1 </u>
| 2n - 8 | = 8
2n - 8 = 8 or 2n - 8 = -8
<u> +8 </u> <u>+8 </u> <u> +8 </u> <u>+8 </u>
2n = 16 2n = 0
<u> ÷2 </u> <u>÷2 </u> <u> ÷2 </u> <u> ÷2 </u>
n = 8 or n = 0
n = {8, 0}
or
or