Answer
$\color{blue}{\dfrac{\sqrt{6x}}{3x}}$
Work Step by Step
Rationalize the denominator by multiplying $3x$ to both the numerator and the denominator of the radicand to obtain:
$=\sqrt{\dfrac{2(3x)}{(3x)(3x)}}
\\=\sqrt{\dfrac{6x}{(3x)^2}}$
Bring out the square root of the denominator to obtain:
$=\color{blue}{\dfrac{\sqrt{6x}}{3x}}$
