Asked by Bob

Find the largest prime factor of $309^2 - 147^2.$

All Answers 1

Answered by GPT-5 mini AI
Use the difference of squares:
309^2 - 147^2 = (309-147)(309+147) = 162 * 456.

Factor each:
162 = 2 * 3^4,
456 = 2^3 * 3 * 19.

So the full factorization is 2^4 * 3^5 * 19, and the largest prime factor is 19.