# Question #7e4ca

Dec 4, 2016

$16 {x}^{3} y - 4 x {y}^{3}$

#### Explanation:

Given -

$4 x y \left(2 x - y\right) \left(2 x + y\right)$
$\left(2 x - y\right) \left(2 x + y\right)$ is in the form of $\left(a - b\right) \left(a + b\right)$

for $\left(a - b\right) \left(a + b\right)$ the answer is ${a}^{2} - {b}^{2}$

Apply this in our problem.

$4 x y \left({\left(2 x\right)}^{2} - {\left(y\right)}^{2}\right)$

Simplify it -

$4 x y \left(4 {x}^{2} - {y}^{2}\right)$

$16 {x}^{3} y - 4 x {y}^{3}$