# How do you simplify (x + 9)(x -2)?

Jan 23, 2017

${x}^{2} + 7 x - 18$

#### Explanation:

Each term in the second bracket must be multiplied by each term in the first bracket. This can be achieved as follows.

$\Rightarrow \left(\textcolor{red}{x + 9}\right) \left(x - 2\right)$

$= \textcolor{red}{x} \left(x - 2\right) \textcolor{red}{+ 9} \left(x - 2\right)$

distribute the brackets.

$= {x}^{2} - 2 x + 9 x - 18$

collect like terms.

$= {x}^{2} + \left(- 2 + 9\right) x - 18$

$= {x}^{2} + 7 x - 18$