If x=y
Multiply by ( x ) -> x^2 = xy
Subtract (y^2) -> (x^2 – y^2) = (xy – y^2)
-> (x-y)(x+y)=y(x-y)
(x-y) cancels from both sides
-> x+y=y
-> y+y = y
-> 2y=y
-> 2=1
????????
2006-09-16 23:59:55 · 6 answers · asked by Anas 3 in Science & Mathematics ➔ Mathematics
ah, age old trick again...
how silly it is to cancel 0 in this equation: 4*0 = 5*0 => 4=5 !
the same thing happens here...
since x=y, x-y=0 and hence you cannot cancel it out....
2006-09-17 00:02:45 · answer #1 · answered by m s 3 · 0⤊ 0⤋
The error lies in cancelling x-y from both sides. This is division by zero
5.0 = 6.0 this does not mean 5 = 6
2006-09-17 00:44:51 · answer #2 · answered by Mein Hoon Na 7 · 1⤊ 0⤋
When you "cancel" both sides by (x-y) you are
dividing by zero since x=y. That's the kind of
problem you encounter with a big no-no in math.
Thou shalt not divide by zero..
2006-09-17 00:06:41 · answer #3 · answered by albert 5 · 0⤊ 0⤋
I dont know why are you playing kids games on yahoo answers... first anything divided by 0 is infinity so better frame it right.
2006-09-17 00:09:45 · answer #4 · answered by webmaster@complete-webs.com 3 · 0⤊ 0⤋
here you can do this operations if only X(multiplied), Y(devided) not be equel ziro, and also not equel eachother (X= noY) till you cancel X-Y in equation. so if X=noY , so how you assumed first X=Y ??? this can not be true.
2006-09-17 00:14:27 · answer #5 · answered by aahs137 3 · 0⤊ 0⤋
You said in the beginning that
x=y.
Then it means (x-y)=0
So it is wrong for you to divide by (x-y) which is zero.
Got it?
2006-09-17 01:19:43 · answer #6 · answered by curious 4 · 1⤊ 0⤋