Proof question of integers.

Question

Let $a$ and $b$ be positive integers such that $ab+1$ divides $a^2+b^2$. Show that $\frac{a^2+b^2}{ab+1}$ is the square of an integer.

this looks like a vieta jumping problem :P – mathworker21 Dec 31 '16 at 06:14 — mathworker21, Dec 31 '16 at 06:14
I googled it. Hahaha thanks a lot – Mathxx Dec 31 '16 at 06:16 — Mathxx, Dec 31 '16 at 06:16

score -1 · Answer 1 · answered Dec 31 '16 at 06:28

-1

answered Dec 31 '16 at 06:28

Harnoor Lal

1 Answers1