Hello,

I have a question regarding a problem that my prof gave me:

x=y

then

x² = xy

x²- y²= xy- y²

(x-y) (x+y) = (x-y) y

x+y= y

y+y=y

2y=y

which would mean that 2=1

Can someoneexplainme where the problem is?

Thanks in adavance!

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- Jan 26th 2010, 11:38 AMchrisjohnston2=1 ?
Hello,

I have a question regarding a problem that my prof gave me:

x=y

then

x² = xy

x²- y²= xy- y²

(x-y) (x+y) = (x-y) y

x+y= y

y+y=y

2y=y

which would mean that 2=1

Can someone**explain**me where the problem is?

Thanks in adavance! - Jan 26th 2010, 11:40 AMrunning-gag
- Jan 26th 2010, 11:40 AMBabyMilo
Mathematical fallacy - Wikipedia, the free encyclopedia

Scroll to Division by zero for your question.

http://upload.wikimedia.org/math/e/3...1820f3e07e.png

:) - Jan 26th 2010, 11:41 AMchrisjohnston
Thanks for your quick replies guys!!!!