Question 186926
7x-y=12 
-3y=7x+8 or -7x-3y=8 now add these 2 equqtions.

7x-y=12
-7x-3y=8
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-4y=20
y=20/-4
y=-5 ans.
7x-(-5)=12
7x+5=12
7x=12-5
7x=7
x=7/7
x=1 ans.