Question 810536
 -x=-2-y
x=2+y
2x-4y=-4
2*(2+y)-4y=-4
4+2y-4y=-4
-2y=-8
y=4
x=2+4
x=6

x = 6,   y = 4

x-y=2
2x-4y=-4
multiply by2
2x-2y=4
subtract 
-4y+2y=8
2y=8
y=4 etc

1 -1 2
2 -4 -4
2 -2 -4
0 2 8
0 1 4
1 -1 2
1 0 6
0 1 4