how to proof 2=1?

* Let a and b be equal non-zero quantities (or)
Let us Assume

a = b ----------------I equation

* Multiply through by a

a^2 = ab

* Both side Subtract by b^2 ,

a^2 - b^2 = ab - b^2

* Left hand side explain with formula [a^2-b^2 = (a-b)(a+b)] and right hand side take common factor

(a - b)(a + b) = b(a - b)

* Both side Divide by (a - b)

a + b = b

* we know that (a=b) in I equation

b + b = b

2b = b

* Both side Divide by the b

2 = 1

Hence proved.