Proof for 1=2
solution:

a=b
a^2=ab
(a^2)-(b^2)=ab-(b^2)
(a+b)(a-b)=b(a-b) => a=b .....(1)
a+b=b
from equation (1)
b+b=b
1+1=1
2=1!!!



Warning : Opps if a=b then (a+b) *0 = b *0 so 0/0