# X^2 - y^2 = x - y , ?

#### khalid_kacst

x^2 - y^2 = x - y , ?????

if y not equal x .

what is y and x when

x^2 - y^2 = x - y

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#### renedox

Only solution I can think of is when x and y is equal to one.
You get:

x = 1; y = 1;

(1)^2 - (1)^2 = (1) - (1)
==> 0 = 0

#### MathematicalPhysicist

Gold Member
Originally posted by renedox
Only solution I can think of is when x and y is equal to one.
You get:

x = 1; y = 1;

(1)^2 - (1)^2 = (1) - (1)
==> 0 = 0
he asked for solution in which x doesnt equal y.

now i know it's simple but the question seems to be simple
x^2-y^2=x-y
(x-y)*(x+y)=x-y /x-y
x+y=1
now for positive integers it could only be x=0 y=1 or the opposite, the other solutions are negative integers and positive ones.

btw, can someone explain how is this a question about calculus?

#### mathman

Unless there is a further restriction on x and y (the original question didn't include any), then x+y=1, for any x, will do.

#### renedox

Originally posted by loop quantum gravity
he asked for solution in which x doesnt equal y.
Gah, don't be tired and browes PF at the same time :P

#### IceZero

use implicit differentiation and find the derivative

#### mathman

use implicit differentiation and find the derivative
What has this got to do with it???????

#### Zargawee

I also wonder the same , and how is that will be useful ?

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