Originally Posted by

**topsquark** No doubt that ThePerfectHacker will want to weigh in on this, but a possible starting point (on a fairly long road!) would be to factor the LHS:

(x + y)(x - y) = 104

Now factor 104:

1, 104

2, 52

4, 26

-1, -104

-2, -52

-4, 26

are all the possibilities.

Now you have to solve simultaneous equations:

x + y = 1

x - y = 104

The solution to this is x = 105/2 and y = -103/2, which aren't integers so this doesn't work. So move on to the next possibility. etc.

I note that there are solutions for all pairs of factors where both factors are even.

-Dan