# How do you solve 78=6(-6a-5) using the distributive property?

Mar 26, 2018

$a = - 18$

#### Explanation:

We want to solve $78 = 6 \left(- 6 a - 5\right)$ using the distributive property

1) Distribute the $6$ on the left-hand side and simplify

$78 = 6 \cdot \left(- 6 a\right) + 6 \cdot \left(- 5\right) = - 36 a - 30$

2) Add $30$ to both sides

$78 + 30 = - 36 a - 30 + 30$

$\Rightarrow 109 = - 36 a$

3) Divide both sides by $- 36$

$\frac{108}{-} 36 = \frac{- 36 a}{-} 36$

$\Rightarrow - 18 = a$

Or, rewriting in a more standard way,

$a = - 18$