9514 1404 393
Answer:
(-4, 10)
Step-by-step explanation:
The inequality is equivalent to the compound inequality ...
-21 < 3x -9 < 21
-12 < 3x < 30 . . . . . . . . . add 9
-4 < x < 10 . . . . . . . . . . . divide by 3
In interval notation, ...
x ∈ (-4, 10)
