b) f(x) ≤ 0 when the function's graph is on or below the x axis.
This happens when the x value is between or equal to -2 or 2
Mathematically we write f(x) ≤ 0 on the interval -2≤ x ≤ 2
All of the above is an important concept that you need to understand. You need to study it.
return