This is a very well know puzzle, but for those who don't know it...

X=Y

X-Y=0

2X-2Y=0

2X-2Y=X-Y

so..

2(X-Y)=1(X-Y)

2=1 !!

This proves that 2=1. Which is impossible. Who can show where these equations are wrong?

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- Jan 27th 2010, 02:38 AM #1

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- Jan 27th 2010, 02:48 AM #2

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## FYI

see also:

http://www.mathhelpforum.com/math-he...oof-1-2-a.html

for more 'proofs' that show 1=2.