Answer :
so
2x+y=2
x+y=-1
multiply secion equation by -1
-x-y=1
add to first equation
2x-x+y-y=2+1
x=3
subsitute
3+y=-1
subtract 3
y=-4
x=3
y=-4
2x+y=2
x+y=-1
multiply secion equation by -1
-x-y=1
add to first equation
2x-x+y-y=2+1
x=3
subsitute
3+y=-1
subtract 3
y=-4
x=3
y=-4