If 3p^2 = q^2 and p and q are integers, how do I prove that 3 is a common divisor for p and q?(adsbygoogle = window.adsbygoogle || []).push({});

My attempt: q^2 is divisible by 3, so q is divisible by 3. I can't prove that p is divisible by 3.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Divisibility and p's and q's

**Physics Forums | Science Articles, Homework Help, Discussion**