# How do you solve the system x + y = 15 and x – y = -19?

May 1, 2018

$x = - 2 \mathmr{and} y = 17$

#### Explanation:

$x + y = 15$
$x - y = - 19$
Add both equations, and it will eliminate y and you will get:
$2 x + 0 y = 15 + \left(- 19\right)$
$2 x = - 4$
$x = - \frac{4}{2}$
$x = - 2$
Now substitute x = 2 in any equation to find value of y:
$- 2 + y = 15$
$y = 15 - \left(- 2\right)$
$y = 17$
$- 2 + 17 = 15$
$- 2 - 17 = - 19$