Answer:
-9 < m < -7 ∪ 7 < m < 9
Step-by-step explanation:
You can proceed in the usual way up to the point where you need to take the square root.
Multiply by 2:
58 < m^2 +9 < 90
Subtract 9:
49 < m^2 < 81
Take the square root:
7 < |m| < 9
This resolves to two sets of inequalities:
7 < -m < 9 ⇒ -9 < m < -7
7 < m < 9
The solution set is the union of these intervals: (-9, -7) ∪ (7, 9).
