How do you solve the system using elimination $x - y = 12$ and $2x + y =3$ ?

Question

4134 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-04-10T20:46:50

We can add the left sides of both equations, and the right sides:

$x-y=12$
$2x+y=3$

Added:
$x-cancely+2x+cancely=12+3->$

$y$ is now eliminated:
$3x=15->x=15div3=5$

Use this in one of the equations:
$2*5+y=3->y=3-10=-7$

Check with the other one:
$5-(-7)=5+7=12$ Check!

How do you solve the system using elimination x - y = 12 x - y = 12 and 2x + y =32x + y =3?