#### Answer

$6x^3\sqrt x$

#### Work Step by Step

$\sqrt[]{4x^7}+9x^2\sqrt[]{ x^3}-5x\sqrt {x^5}$ Factor.
$\sqrt{4 x^6}\cdot\sqrt {x}+9x^2\sqrt{ x^2}\sqrt x-5x\sqrt{x^4}\sqrt x $ Simplify.
$2x^3\sqrt x+9x^3\sqrt x-5x^3\sqrt x $ Combine like radicals.
$6x^3\sqrt x$