# How do you solve 9a + 15 =10a - 7?

May 31, 2016

$a = 22$

#### Explanation:

Given,

$9 a + 15 = 10 a - 7$

Subtract $9 a$ from both sides.

$9 a \textcolor{w h i t e}{i} \textcolor{red}{- 9 a} + 15 = 10 a \textcolor{w h i t e}{i} \textcolor{red}{- 9 a} - 7$

$15 = a - 7$

Add $7$ to both sides.

$15 \textcolor{w h i t e}{i} \textcolor{red}{+ 7} = a - 7 \textcolor{w h i t e}{i} \textcolor{red}{+ 7}$

$a = \textcolor{g r e e n}{| \overline{\underline{\textcolor{w h i t e}{\frac{a}{a}} \textcolor{b l a c k}{22} \textcolor{w h i t e}{\frac{a}{a}} |}}}$