Question

Proof that 2=1?
a = b
a^2 = a*b
a^2-b^2 = a*b-b^2
(a+b)(a-b) = b(a-b)
(a+b) = b
a+a = a
2a = a
2 = 1

Where and is the equation
incorrect? Or does 2 really equal 1?