#### Answer

$2|x|\sqrt{10x}$

#### Work Step by Step

Factor the radicand (expression inside the radical sign) so that at least one factor is a square to obtain:
$=\sqrt{4x^2(10x)}
\\=\sqrt{2^2x^2(10x)}$
The principal square root is always non-negative.
Thus, to make sure that the principal square root of $x^2$ is non-negative, use absolute value bars to obtain:
$=2|x|\sqrt{10x}$