# How do you solve: 4a - 4 = 8 + a?

May 25, 2017

See a solution process below:

#### Explanation:

First, add $\textcolor{red}{4}$ and subtract $\textcolor{b l u e}{a}$ to each side of the equation to isolate the $a$ term while keeping the equation balanced:

$4 a - 4 + \textcolor{red}{4} - \textcolor{b l u e}{a} = 8 + a + \textcolor{red}{4} - \textcolor{b l u e}{a}$

$4 a - \textcolor{b l u e}{a} - 4 + \textcolor{red}{4} = 8 + \textcolor{red}{4} + a - \textcolor{b l u e}{a}$

$4 a - \textcolor{b l u e}{1 a} - 0 = 12 + 0$

$\left(4 - \textcolor{b l u e}{1}\right) a = 12$

$3 a = 12$

Now, divide each side of the equation by $\textcolor{red}{3}$ to solve for $a$ while keeping the equation balanced:

$\frac{3 a}{\textcolor{red}{3}} = \frac{12}{\textcolor{red}{3}}$

$\frac{\textcolor{red}{\cancel{\textcolor{b l a c k}{3}}} a}{\cancel{\textcolor{red}{3}}} = 4$

$a = 4$