Olympiad Maths Prep

Track / Stage 4 / 218 of 340 #478 of 2000

Problem 478

AMC 12 late, AIME early
Number theory Difficulty 4.9 Find the answer

2 [

Find all pairs of prime numbers, the difference of the squares of which is a prime number.

#

Official solution

Let pp and qq be prime numbers and p2q2=(pq)(p+q)p^{2}-q^{2}=(p-q)(p+q) be a prime number. Then pq=1p-q=1. Therefore, one of our numbers is even, that is, q=2,p=3q=2, p=3.

## Answer

(3,2)(3,2).

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic, difficulty and ordering added by this site.