Is this proof that 1+1=3?

Question

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."

Answer 1

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.)

Answer 2

2 2 1 at a time

Answer 3

well if you look at it this way 1 +1 wouldnt necessarily = 3 either it could iqual 4,5,6,7 etc. take 1 male and 1 female and put them together and with in a short time you will end up with 3 you normally end up with at least 1 baby so the 1 and the 1 ended up being 3. Truthfully I have no idea how 1 +1 could iqual 3 unless the 1's were not whole 1's and you do some rounding off. Math is not one of my subjects. you could also look at it this way too . you can have 1 car and 1 boat which iqual 5 tires including the spare. except if the boat is on a trailer then you would have 9 tires including the spare for the car and 10 if you have a spare for the trailer. If someone were to all of a sudden change the numerical system I think that would screw things up quiet a bit. So maybe we should just leave 1+1= 2 .

Answer 4

Proof of 1+1=2

You have one cookie. Then you received another cookie. You have not three, but 2 cookies. To find proof of 1+1=3, you would have to go to a completely diffrent universe with completely diffrent mathematics.

Answer 5

The ting you did wrong was dividing x(x-y) by (x-y), because if x = y, means that x - y = 0 => x / 0 = \inf
so:
x = y
-x2= -xy
x2 - y2 = x2 - xy
(x + y)(x - y) = x(x - y)
(x + y)(x - y) = x(x - y)
x^2-y^2 = x(x-y)
xy-xy = xx-xy
xy = xx
y = x

2 = 2

Answer 6

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

Answer 7

in Algebra when a answer equals 2 numbers such as 5=3 it is a false statement! 2=1 is not correct algebra

Answer 8

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.

Answer 9

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

Answer 10

that doesnt make any sence at all.... its BS