Answer
$5|x|\sqrt{5}$
Work Step by Step
RECALL:
For any non-negative real numbers $a$ and $b$,
$\sqrt{ab} = \sqrt{a}\cdot \sqrt{b}$ and $\sqrt{a} \cdot \sqrt{b} = \sqrt{ab}$.
Factor the radicand so that one factor is a perfect square to obtain
$\sqrt{9x^2 \cdot 5}$.
Use the rule above to obtain
$\sqrt{25x^2} \cdot \sqrt{5}
\\=\sqrt{(5x)^2} \cdot \sqrt{5}.$
Note that the variable $x$ represents any real number. This means that $x$ could be negative. Thus, to simplify the expression, use the rule $\sqrt{a^2}=|a|$ to obtain
$|5x|\sqrt{5}
\\=5|x|\sqrt{5}.$
