Answer
(a) $f(2)=5$
(b) $f(-1)=11$
Work Step by Step
(a) Here we require the y-value of the ordered pair when $x=2$. As indicated by the ordered pair $(2,5)$, when $x=2$, $y=5$. Therefore, $f(2)=5$.
(b) Here we require the y-value of the ordered pair when $x=-1$. As indicated by the ordered pair $(-1,11)$, when $x=-1$, $y=11$. Therefore, $f(-1)=11$.