x = y
x squared = xy -----(multiply by x)
x squared - y squared = xy - y squared -----(subtract y2 from both sides)
(x + y)*(x - y) = y (x - y) -----(factorizing)
x + y = y -----(dividing by (x - y)
2y = y -----(substituting for x = y, the original premise)
2 = 1 -----(dividing by y)
Assert the truth with confidence!!!