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.

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# Divisibility and p's and q's

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