Answer
$3$
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.
$\lim_\limits{x\to -1}\sqrt {5x^2+4}=\sqrt {5(-1)^2+4}=\sqrt{5+4}=3$
