3(3) - 2y = -7

9 - 2y = -7

9 + 7 = 2y

16 = 2y

y = 16/2

y= 8

to prove:

3(3) - 2(8) = -7

9 - 16 = -7

@sarvesh:

You've done a mistake as it is not y= -8 it is -y= -8 which is the same as y=8

3x -2y = -7

when x=3 then 3x = 9

9 - 2y = -7

2y = -7-9

2y = -16

y = = -8

I found that y = -8 only integer deffierence