. Applying some basic identity transformations, we get:
With such a proof, we can show that
1=2, pi=E, 10000000000000=1, etc.... Can you spot the flaw?
First of all a*a - a*b is zero though not a flaw. But the removing of (a - b) on both sides in 3rd statement is not valid as (a - b) = 0. This is the flaw.