Question

Determine the largest prime number that
you need to test osakor, to find
dihether or not 397 is a prime number​

Answer 1

Answer:

If we test 2,3,5,7,11,13,17,19 as divisor for 397 then we get following results

1.397 is not divisible by 2 because of not even number

2.not divisible by 3 because sum of 3+9+7=19

3.not divisible by 5 because unit place number is not 0/5

4.not divisible by 7,but 397÷7= 56 is quotient and 5 is reminder

5.not divisible by 11,but 397÷11 =36 is quotient and 1 is reminder

6.not divisible by 13 but 397÷13=30 is quotient and 7 is reminder

7.not divisible by 17 but 397÷17=23 is quotient and 6 is reminder

8.not divisible by 19but 397÷19=20 is quotient and 17is reminder

Here we do not take 23 as divisor because the reminder 20 when 397 is divided by 19 and that is less than 23 .so 397 is prime number and 19 is the largest prime for the number 397.

Step-by-step explanation:

hope it helps you