# How do I find the cube of (2 x + 5)?

Apr 1, 2018

$8 {x}^{3} + 65 {x}^{2} + 150 x + 125$

#### Explanation:

$\left(2 x + 5\right)$ cubed = ${\left(2 x + 5\right)}^{3}$

${\left(2 x + 5\right)}^{3} = \left(2 x + 5\right) \left(2 x + 5\right) \left(2 x + 5\right)$

First, do $\left(2 x + 5\right) \left(2 x + 5\right) = 4 {x}^{2} + 20 x + 25$

Now do the second part: $\left(4 {x}^{2} + 20 x + 25\right) \left(2 x + 5\right)$

$8 {x}^{3} + 65 {x}^{2} + 150 x + 125$