The expression you provided is:

$\sqrt{18x^3y^6}$

Let's simplify this expression into its simplest radical form.

Step 1: Prime factorization of the numerical part

First, factorize 18:

$18 = 2 \times 3^2$

Step 2: Rewrite the square root expression

We can express the square root as:

$\sqrt{18x^3y^6} = \sqrt{2 \times 3^2 \times x^3 \times y^6}$

Step 3: Simplify inside the square root

We