Respuesta :
3x+3y=-9
Add -3y to both sides.3x+3y+−3y=−9+−3y3x=−3y−9
you can divide
3x/3= -3y-9/3
x= -y-3
3x-3y=21
x=y+7
Add -3y to both sides.3x+3y+−3y=−9+−3y3x=−3y−9
you can divide
3x/3= -3y-9/3
x= -y-3
3x-3y=21
x=y+7