Proof of Theorem that 4=5 (joke for christmas)

[Yohannes Yaali]

Nasrul Indroyono wrote:

>Does anybody know what's wrong with this theorem ?

>Theorem: 4 = 5
>Proof:
>16 - 36 = 25 - 45
> 4^2 - 9*4 = 5^2 - 9*5
> 4^2 - 9*4 + 81/4 = 5^2 - 9*5 + 81/4

I don't think that 9*4 is equal to 9*5.

>(4 - 9/2)^2 = (5 - 9/2)^2
>4 - 9/2 = 5 - 9/2
>4 = 5

>merry christmas every body and happy new year !!

>Nasrul Indroyono

Rgds,
Yohannes Yaali
[EMAIL PROTECTED]