# How do you solve 3x - y = 9 and 2x + y = 6?

Aug 3, 2015

I fond:
$x = 3$
$y = 0$

#### Explanation:

You can add the two equations (in columns):
{3x-y=9
{2x+y=6

$5 x + 0 = 15$
So:
$x = \frac{15}{5} = 3$
substitute this back into the first equation:
$3 \cdot 3 - y = 9$
$9 - y = 9$
$y = 0$