Answer
$6$
Work Step by Step
Recall that if $ f $ is a polynomial function, then we have $\lim_\limits{x\to a}f(x)=f(a)$.
In order to to find the limit, we will plug $ a $ into the function and then simplify.
$\lim_\limits{x\to 3} \dfrac{x^2-9}{x-3}=\lim_\limits{x\to 3} \dfrac{(x-3)(x+3)}{x-3}$
or, $= \lim_\limits{x\to 3}(x+3)$
or, $=6$
