Question 160337
2x-y=-1 multiply his equation by 2 & add them.
3x+2y=30
4x-2y=-2
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7x=28
x=28/7
x=4 answer.
2*4-y=-1
8-y=-1
-y=-1-8
-y=-9
y=9 answer.
proof:
3*4+2*9=30
12+18=30
30=30