#### Answer

$2x\times\sqrt[3]{2x}$

#### Work Step by Step

$\sqrt[3]{16x^4}$
Factor out the perfect cubes.
$\sqrt[3]{8\times2\times x^3\times x}$
Use the product rule for nth roots.
$\sqrt[3]{8}\times\sqrt[3]2\times\sqrt[3]{x^3}\times\sqrt[3]{x}$
Simplify.
$2\times\sqrt[3]2\times x\times\sqrt[3]{x}$
Use the product rule for nth roots.
$2x\times\sqrt[3]{2x}$