Answer
See below:
Work Step by Step
(b)
Consider the given function:
$f\left( x \right)=\left\{ \begin{align}
& \text{4 if }x\le -1 \\
& -4\text{ if }x>-1
\end{align} \right.$
The graph of the function f consists of two parallel straight lines also parallel to the x axis.
As it can be determined, the range of the function is $\left\{ -4,4 \right\}$.
Thus, the range of the function is $\left\{ -4,4 \right\}$.