Answer
$72x^2y$
Work Step by Step
Use the rule $\sqrt{a} \cdot \sqrt{b} = \sqrt{ab}$ where $a,b>0,$ to obtain:
$=(6 \cdot 2) \sqrt {4 \cdot 9 \cdot x^2 \cdot x^2 \cdot y^2}$
Simplify:
$=12 \sqrt {36 \cdot x^4 \cdot y^2}$
Factor the radicand:
$=12 \sqrt {6^2 \cdot (x^2)^2 \cdot y^2}$
Take the square roots:
$=12 \cdot 6 \cdot x^2 \cdot y$
$=72x^2y$
