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