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I'm requested to find the product of all quadratic irreducible polynomials of $\mathbf{Z}_{3}[x]$ . How can I find them ? brute force ? check that every polynomial has no roots ?

Or , if I take for example $f(x)=ax^2 + bx +c $ , find restrictions for a,b & c ?

I'd appreciate your help

Regards

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    Why not "brute force"? It is a small problem. You probably mean *monic* quadratic irreducible.2012-03-20

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I think you are asking for all the polynomials of degree 2 irreducible over ${\bf Z}_3$. Let $f(x)=ax^2+bx+c$. You may assume $a=1$ (why?). You may assume $c\ne0$ (why?). That leaves you only six polynomials to check (why?).

Alternatively, you could argue that if it's not irreducible it must be a product of two linear factors. So once you get rid of $x^2,x(x-1),\dots,(x-2)^2$, the remaining (monic) polynomials must be irreducible.

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    @Bill, my answer went up before OP's comment and before Jyrki's edit. My answer still speaks to the question about "find(ing) restrictions for $a$, $b$, and $c$."2012-03-20