# If 8x+5(3+x)-a=15+5x, then what is a?

Aug 4, 2015

$a = 8 x$

#### Explanation:

Your equation looks like this

$8 x + 5 \cdot \left(3 + x\right) - a = 15 + 5 x$

The terms that can be found on both sides of the equation can be cancelled out

$8 x + \textcolor{red}{\cancel{\textcolor{b l a c k}{15}}} + \textcolor{b l u e}{\cancel{\textcolor{b l a c k}{5 x}}} - a = \textcolor{red}{\cancel{\textcolor{b l a c k}{15}}} + \textcolor{b l u e}{\cancel{\textcolor{b l a c k}{5 x}}}$

$8 x - a = 0$

To solve this equation for $a$, you need to isolate it on one side of the equation.

This can be done by adding $a$ to both sides of the equation to get

$8 x - \textcolor{red}{\cancel{\textcolor{b l a c k}{a}}} + \textcolor{red}{\cancel{\textcolor{b l a c k}{a}}} = a$

Therefore,

$a = \textcolor{g r e e n}{8 x}$