# What is the standard form of y= (x^2-4)(2x+9) -(x+5)^2?

Jan 28, 2016

$2 {x}^{3} + 8 {x}^{2} - 18 x - 61$

#### Explanation:

Multiply both factors:
$2 {x}^{3} + 9 {x}^{2} - 8 x - 36 - \left({x}^{2} + 10 x + 25\right)$

Distribute the negative sign through the terms in the parenthesis:
$2 {x}^{3} + 9 {x}^{2} - 8 x - 36 - {x}^{2} - 10 x - 25$

Consolidate like terms:
$2 {x}^{3} + \left(9 {x}^{2} - {x}^{2}\right) + \left(- 8 x - 10 x\right) + \left(- 36 - 25\right)$
$2 {x}^{3} + 8 {x}^{2} - 18 x - 61$