Answer:
-3 ≤ x <-2
Step-by-step explanation:
First, you should set up the equation to solve it, which is,
21 ≤ -3(x-4)<18
Then you should simplify the equation to,
21 ≤ -3x+12<18
Then subtract 12 from both sides.
9 ≤ -3x<6
Lastly, divide -3 from both sides.
-3 ≤ x<-2
