Answer :
[tex]x-y=-3 \ \ => \boxed{x=-3+y} \\ \\ 2x+y=12 \\ \\ 2(-3+y)+y=12 \\ \\ -6+2y+y=12 \\ \\ 3y=12+6 \\\\ 3y=18 \\ \\ \boxed{y=\frac{18}{3}=6} \\ \\ x=-3+6 \\ \\ \boxed{x=3}[/tex]
x - y = 3
2x + y = 12
x = 3 + y
2(3 + y) + y = 12
6 + 2y + y = 12
3y = 12 - 6
3y = 6
y = 6/3
y = 2
x = 3 + 2
x = 5
2x + y = 12
x = 3 + y
2(3 + y) + y = 12
6 + 2y + y = 12
3y = 12 - 6
3y = 6
y = 6/3
y = 2
x = 3 + 2
x = 5
