Answer
$3$
Work Step by Step
When $f(x) \geq 0$ then, we have $\lim\limits_{x \to a} \sqrt {k(x)}=\sqrt {\lim\limits_{x \to a} k(a)}$
where $a$ is a constant.
Thus, we have:
$\lim\limits_{x \to 1} \sqrt {5x+4}=\sqrt {\lim\limits_{x \to 1} (5x+4)} \\=\sqrt {(5)(1)+4} \\=\sqrt 9 \\=3$
