Answer
a. $ -\infty$
b. $ -1$
c. $ -1$
d. Is not continuous
Work Step by Step
From the given figure, we get
a. $\lim _{x \rightarrow 6^{-}} f(x)= -\infty$
b. $\lim _{x \rightarrow 6^{+}} f(x)= -1$
c. $f(6)=-1$
d. $f$ is not continuous at $x=6$, because
$$ \lim _{x \rightarrow 6^{+}} f(x)\neq \lim _{x \rightarrow 6^{+}} f(x)$$
