Answer
$2x\sqrt{{6x}}$
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:
$=\sqrt{4x^2(6x)}
\\=\sqrt{(2x)^2(6x)}
\\=2x\sqrt{{6x}}$