Question

prove \(397\) is prime

Answer 1

hint given : \(397 = 20^2-3\)

Answer 2

Use Prime Factorization Method

Answer 3

no number under 20 divides it so

Answer 4

other than 1

Answer 5

so the proof contains 19 divisibility tests ?

Answer 6

primes under 20 are
2,3,5,7,11,13,17

Answer 7

19*

Answer 8

thats better, 8 divisibility tests since there are only 8 primes under 20

any other method