y = 4 and x = 3

(2x + 4)⁄(x - 4) = (x + 3)⁄(x + 5)      I will use * as x (times)    

So if y=4 and x=3...

(2x + 4) (x - 4 )

2x * x = 2x²       2x²-4x-16            

4 x -4 = -16

2x * -4 = -8x

4 x * = 4x

Aaaand that's just about all that I could be bothered to do....

So, I'm sorry if you were expecting some sort of incredible genius answer, I'm not a genius.