Respuesta :

so solving by addition !

6x= 12
x= 2

and y = -5
3x+3y=-9
Add -3y to both sides.3x+3y+3y=−9+3y3x=3y9
you can divide
3x/3= -3y-9/3
 x= -y-3

3x-3y=21
x=y+7