Question 171922
Assume you mean:
{{{sqrt((18x^5)/y^2)}}}
:
Factor to reveal the perfect squares inside the radical
{{{sqrt((3*3*2*x^2*x^2*x)/(y*y))}}} 
:
Extract the square root of the perfect squares and you have;
{{{(3x^2)/y}}}*{{{sqrt(2x)}}}