Is this proof that 1+1=3?

A friend agave me this puzzling proof that 1=1=3. It sounds stupid but look:


x = y


-x2= -xy


x2 - y2 = x2 - xy


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


x + y = x


1 + 1 =2


2 = 1


I can't believe it!





PS the "2" at the end is a "squared."

Is this proof that 1+1=3?
You have a couple of typos, I think. As for the "proof", dividing by x - y is dividing by zero. That is a no-no. (In other words, a * 0 = b * 0 does not imply a = b.)
Reply:IF X=Y AND XPLUS Y = X THEN X=0 AND Y= 0 OR YOU ARE NOT WRITING EQUATIONS, NOT MAKING TRUE STATEMENTS Report It

Reply:This really makes no sense. A proof is valid if and only if logic leads you from one step to another. This is a bunch of unrelated statements, the last of which is incorrect.
Reply:The step where you divided both sides by x - y is valid in general, but it isn't valid here:





Recall that in the initial step, x = y. If x = y, then x - y = 0.





So in the step where you cancelled the x-y on both sides, both sides were divided by 0, which is invalid in our number system.





Or to put it another way, once you do the impossible, anything can happen! :D
Reply:in Algebra when a answer equals 2 numbers such as 5=3 it is a false statement! 2=1 is not correct algebra
Reply:there is one problem





1+1=2


2=1





but wouldn't you subtract 1 on both sides?





1+1=2


-1 -1


1=1
Reply:that doesnt make any sence at all.... its BS