# How do you solve -9(a + 16) + (-4) = 23?

Jul 16, 2015

$\textcolor{red}{a = - 19}$

#### Explanation:

$- 9 \left(a + 16\right) + \left(- 4\right) = 23$

Remove parentheses from the $- 4$:

$- 9 \left(a + 16\right) - 4 = 23$

Distribute the $- 9$:

$- 9 a - 144 - 4 = 23$

Combine like terms:

$- 9 a - 148 = 23$

Add $148$ to each side:

$- 9 a = 171$

Divide both sides by $- 9$:

$a = - \frac{171}{9}$

$a = - 19$

Check:

-9(a+16) + (-4) = -9(-19+16)-4 = -9×(-3)-4 = 27-4 = 23