Question

Plz help. If A and B are two non-empty sets such that AxB = BxA, show that A=B?

Answer 1

This might be too late to be of any use, but I'll do it anyway :)
Let a be an element of A
Let b be an element of B

Then (a,b) is in AxB
Since AxB = BxA
Then
(a,b) is in BxA
Then
a is in B
and
b is in A
Therefore, A is a subset of B
and B is a subset of A

Thus, A = B
QED