2=1

Assume....................................................a = b
Multiply both sides by a..............................a2 = ab
Subtract b2 from both suides.....................a2-b2 = ab-b2
Factor both sides...................................(a-b) (a+b) = b(a-b)
Divide both sides by (a-b)............................a+b = b
But a = b so.............................................b+b =b
or...........................................................2 =1