Let f(X) = X2 + X + 1 and g(X) = X2 + X - 2 be polynomials in ℤ[X]. Which of the following statements are true?
1
For all prime numbers p, f (X) mod p is irreducible in (ℤ/pℤ) [X].
2
There exists a prime number p such that g(X) mod p is irreducible in
(ℤ/pℤ) [X].
(ℤ/pℤ) [X].
3
g(X) is irreducible in ℚ[X].
4
f(X) is irreducible in ℚ[X].