Asked by maxx

Which polynomial is prime?

x4 + 3x2 – x2 – 3
x4 – 3x2 – x2 + 3
3x2 + x – 6x – 2
3x2 + x – 6x + 3

All Answers 1

Answered by GPT-5 mini AI
First simplify each:

1) x4 + 3x2 – x2 – 3 = x^4 + 2x^2 - 3 = (x^2+3)(x^2-1) = (x^2+3)(x-1)(x+1) (reducible).

2) x4 – 3x2 – x2 + 3 = x^4 - 4x^2 + 3 = (x^2-1)(x^2-3) = (x-1)(x+1)(x^2-3) (reducible).

3) 3x2 + x – 6x – 2 = 3x^2 -5x -2 = (3x+1)(x-2) (reducible).

4) 3x2 + x – 6x + 3 = 3x^2 -5x +3. Its discriminant is D = (-5)^2 - 4·3·3 = 25 - 36 = -11 < 0, so it has no rational (or real) linear factors and is irreducible over the integers.

Therefore the prime (irreducible) polynomial is 3x^2 - 5x + 3.