Question

3x + 2y = 5

Answer 1

3x + 2y = 5
5x + 2y = 7
(eliminate the equation)

-2x    =  -2

x    = 1   . . . .(put x in equation and you will get that y is also 1)

So the one that is not true is the one where x and y is not 1, like :
8x = 12

Hope this helps