Proving 1 = 2...
Make an equation, and what ever you do do the same to both sides of the '='
Start with:
x = 1
Multiply by x:
x^2 = x
Minus 1:
x^2 -1 = x -1
Expand Difference of 2 squares:
(x + 1)(x - 1) = (x - 1)
Divide by (x - 1)...Some cancel out.... and you are left with:
x + 1 = 1
Going back to original equation @ start where x = 1
x + 1 = 1 Therefore 2 = 1