# Proof of composites

1. Oct 2, 2008

### phyguy321

Prove that if p $$\geq$$ 5 is prime, then p$$^{2}$$ +2 is composite
(hint: work mod 3 and use #5 to show p^2 + 2 has a factor of 3.)

2. Oct 2, 2008

### tiny-tim

Hi phyguy321!

Show us what you've tried, and where you're stuck, and then we'll know how to help.

(and … erm … what's #5? )

3. Oct 3, 2008

### phyguy321

The problem is i have no idea of where to start. Modular arithmetic makes no sense to me. and #5 was my other post on modular arithmetic

4. Oct 3, 2008

### tiny-tim

Last edited by a moderator: Apr 23, 2017