Step-by-step explanation:
9 ≤ |4x + 7|
9 ≤ 4x + 7
9 - 7 ≤ 4x
2 ≤ 4x
2/4 ≤ x
9 ≤ -(4x + 7)
9 ≤ -4x - 7
9 + 7 ≤ -4x
16 ≤ - 4x
16/-4 ≤ x