# How do you simplify (5 – 2x)(x + 3) times (x + 7)?

Jun 18, 2018

Expand the brackets first

$\left(5 - 2 x\right) \left(x + 3\right)$

$5 x + 15 - 2 {x}^{2} - 6 x$

$15 - 2 {x}^{2} - x$

Now multiply this by $\left(x + 7\right)$

$15 x - 2 {x}^{3} - {x}^{2} + 105 - 14 {x}^{2} - 7 x$

$- 2 {x}^{3} - 15 {x}^{2} + 8 x + 105$