# How do you factor u^3-2u^2-8u+16?

Refer to explanation

#### Explanation:

It is

${u}^{3} - 2 {u}^{2} - 8 u + 16 = {u}^{2} \left(u - 2\right) - 8 \left(u - 2\right) = \left({u}^{2} - 8\right) \left(u - 2\right) = \left(u - \sqrt{8}\right) \left(u + \sqrt{8}\right) \left(u - 2\right) = \left(u - 2 \sqrt{2}\right) \left(u + 2 \sqrt{2}\right) \left(u - 2\right)$

Sep 23, 2015

You can collect ${u}^{2}$ from the first and third term and $- 8$ from the second and fourth to get:
${u}^{2} \left(u - 2\right) - 8 \left(u - 2\right) =$
Now collect $\left(u - 2\right)$ and get:
$= \left(u - 2\right) \left({u}^{2} - 8\right)$