Question 579194
x=5+y
2x-3y=7
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2(5+y)-3y=7
10+2y-3y=7
-y=7-10
-y=-3
y=3
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2x-3*3=7
2x-9=7
2x=7+9
2x=16
x=8
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proof
x=5+y
8=5+3