Can anybody help me out with this problem? I don't need a huge explanation but a very brief explanation on how you got the answer. Thanks!

ANSWER:
4
13
8
STEP-BY-STEP EXPLANATION:
We can calculate the value in each case by means of the graph, just like this:
Therrefore:
[tex]\begin{gathered} f(0)=4 \\ f(3)=13 \\ f(-2)=8 \end{gathered}[/tex]