# How do you simplify (4x^2 + 15x - 18) - (9x^2 - 5x + 19) - (-5x^2 + 18x - 20) - (-4x^2 - 7x + 15)?

Jun 18, 2015

$= \textcolor{red}{4 {x}^{2}} + \textcolor{b l u e}{9 x} - 32$

#### Explanation:

$4 {x}^{2} + 15 x - 18 - 9 {x}^{2} + 5 x - 19 + 5 {x}^{2} - 18 x + 20 + 4 {x}^{2} + 7 x - 15$

Grouping like terms:
$\textcolor{red}{\left(4 {x}^{2} - 9 {x}^{2} + 5 {x}^{2} + 4 {x}^{2}\right)} + \textcolor{b l u e}{\left(15 x + 5 x - 18 x + 7 x\right)} + \left(- 18 - 19 + 20 - 15\right)$

$= \textcolor{red}{4 {x}^{2}} + \textcolor{b l u e}{9 x} - 32$