Can anybody help me get the answer to this problem? I don't need a huge explanation on how you got it but a very brief explanation as I am low on time. Thanks!

As given by the question
There are given that the graph.
Now,
The value of f(4) is:
[tex]\begin{gathered} f(x)=y \\ f(4)=0 \end{gathered}[/tex]And
If f(x)=5, then x is:
[tex]\begin{gathered} f(x)=5 \\ f(x)=y \\ f(2)=5 \end{gathered}[/tex]Hence, the value of f(4) is 0 and x is 2.