# How do you solve -5(5n – 7) – 4 = 56?

Jul 28, 2015

Expand the paranthesis and isolate $n$ on one side of the equation.

#### Explanation:

Your stating equation is

$- 5 \left(5 n - 7\right) - 4 = 56$

First, use the distributive property of multiplication to get

$- 5 \cdot 5 n - 5 \cdot \left(- 7\right) - 4 = 56$

$- 25 n + 35 - 4 = 56$

$- 25 n + 31 = 56$

Next, add $- 31$ to both sides of the equation to get

$- 25 n + \textcolor{red}{\cancel{\textcolor{b l a c k}{31}}} - \textcolor{red}{\cancel{\textcolor{b l a c k}{31}}} = 56 - 31$

$- 25 n = 25$

Finally, divide both sides of the equation by $- 25$ to get

$\frac{\textcolor{red}{\cancel{\textcolor{b l a c k}{- 25}}} \cdot n}{\textcolor{red}{\cancel{\textcolor{b l a c k}{- 25}}}} = \frac{25}{- 25}$

$n = \textcolor{g r e e n}{- 1}$