You can put this solution on YOUR website! 2x-y=12
2x=y+12
x=y/2+12/2
x=y/2+6
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2x-y=12
-y=-2x+12
y=2x-12
y=2(x-6)
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there is an infinite number of solution for x & y.
if x=6 then 6=y/2+6
y/2=6-6
y/2=0
y=0
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if y=12 then 12=2(x-6)
12=2x-12
2x=24
x=24/2
x=12
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try some other x or y values to prove the point.