Answer
For all $a$ in the domain of $r.$
Work Step by Step
Theorem 2.4.b states that
$\displaystyle \quad \lim_{x\rightarrow a}\frac{p(x)}{q(x)}=\frac{p(a)}{q(a)},$ provided $q(a)\neq 0$.
If $r(x)=\displaystyle \frac{p(x)}{q(x)}$, a rational function, then the statement of the theorem reads
$\displaystyle \lim_{x\rightarrow a}r(x)=r(a)$,
for all $a$ in the domain of $r.$
