#### Answer

$y^2\sqrt{x}$

#### Work Step by Step

RECALL:
For any non-negative real number,
$\sqrt{a^2} = a$
Factor the radicand (which is the expression inside the radical sign) so that at least one factor is a square, and then simplify using the rule above to obtain:
$=\sqrt{(y^4)(x)}
\\=\sqrt{(y^2)^2(x)}
\\=y^2\sqrt{x}$