Answer
$2x\sqrt3$
Work Step by Step
$\sqrt{6x}\times\sqrt{2x}\longrightarrow$ multiplication property of square roots
=$\sqrt{6x\times2x}\longrightarrow$ simplify
=$\sqrt{12x^2}\longrightarrow$ factor out perfect square
=$\sqrt{4x^2\times3}\longrightarrow$ multiplication property of square roots
=$\sqrt{4x^2}\times\sqrt3\longrightarrow$ simplify
=$2x\sqrt3$