Question

The GCD of x^5+x^4+x^3 – x^2 – x + 1 and x^3 + x^2 + x + 1 over GF(3) is

(a) 1

(b) x

(c) x + 1

(d) x^2 + 1

I had been asked this question during a job interview.

Query is from Polynomial and Modular Arithmetic- IV in chapter Basic Concepts in Number Theory and Finite Fields of Cryptograph & Network Security

Answer 1

Correct answer is (c) x + 1

To explain I would say: The GCD of x^5+x^4+x^3 – x^2 – x + 1 and x^3 + x^2 + x + 1 over GF(3) is x + 1.