Answer
$3x^2\sqrt{x}$
Work Step by Step
Use $9=3^2$.
$\sqrt{9x^5}=\sqrt{3^2x^4\cdot x}$
Use properties of radicals.
$=\sqrt{3^2x^4}\sqrt{x}$
$=\sqrt{3^2(x^2)^2}\sqrt{x}$
$=\sqrt{(3x^2)^2}\sqrt{x}$
Simplify.
$=3x^2\sqrt{x}$
Hence, the correct answer is $3x^2\sqrt{x}$.
