Find 4 different positive integers A,B,C,D for which:
A+B = C*D and
A*B = C+D
How many sets of 4 numbers can you find? Prove that only those sets exist.
(In reply to re: No Subject
Tristan, I was trying to solve this problem on-line. So, when I thought I had achieved the answer, I posted my "solution", and, surprisingly, I saw the counter-example (look at the time of the postings).
You´re absolutely right, there´s some flaw in my reasoning.
It seems that Gamer´s reasoning leaves no doubt.
Posted by pcbouhid
on 2005-07-22 15:56:06