Answer:
D
Step-by-step explanation:
Given
21 ≤ - 3(x - 4) < 30
Divide all intervals by - 3, reversing the inequality symbols as a result of dividing by a negative quantity.
- 7 ≥ x - 4 > - 10 ( add 4 to each interval )
- 3 ≥ x > - 6, that is
- 6 < x ≤ - 3 → D
