Question

Find the largest prime divisor of 76^2 − 1.

Answer 1

Answer:

11

Step-by-step explanation:

This is a difference of squares and therefore can be written as (76-1)(76+1)=(75)(77).

So lets look at the factors....

75=3(25)=3(5)(5)

77=7(11)

The biggest prime factor is therefore 11.

Identities used:

Difference of squares a^2-b^2=(a-b)(a+b)