Can the sum of squares of two rational numbers equal 14?
If so, give an example.
If not, prove it.

(In reply to re: Fixing the prior proof (spoiler) by xdog)

OK, xdog, I am convinced.  You are correct.   If A and B are odd, then 7C^2 = 1 mod 4.  But this is not possible, and your proof works.

Posted by Steve Herman on 2015-05-08 12:05:03