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0 votes
1 answer
69 views

Reducible/Irreducible Polynomials in Ring Theory

I have this following exercise I've been trying to solve for a while now. We are supposed to study the irreducibility of the polynomial $A=X^4 +1$ in $\mathbb{Z}[X]$ and in $\mathbb{Z}/p \mathbb{Z}$ ...
Seramiti's user avatar
5 votes
1 answer
104 views

Define $f(x) = x^6 + x^5 + 3x^4 +x^3 + 3x^2 + x + 1$. Find the largest prime factor of $f(19) + 1$ (Homework) [closed]

Define $f(x) = x^6 + x^5 + 3x^4 +x^3 + 3x^2 + x + 1$. Find the largest prime factor of $f(19) + 1$ This problem is from a homework set of my class at source: Alphastar.academy. I believe there a ...
Joshua Yang's user avatar
1 vote
1 answer
271 views

Using the remainder theorem to prove a quadratic is a factor of a polynomial

For example, if I have $P(x) = 3x^4 + 5x^3 -17x^2 -13x + 6$ then to show that $x^2 + x - 6$ is a factor I individually show that $x+3$ and $x-2$ are factors using the factor theorem (i.e. $P(-3) = 0$ ...
user523384's user avatar
2 votes
0 answers
39 views

Irreducibility of polynomials in $F[X]$

Let $f = 3X^4 + 2X^3Y + X^2Y^2 + 3XY^3 + Y^4$. Let $R =\mathbb{Z}[Y]$, $F = Frac[R]$. I want to know whether or not $f$ is irreducible in $F[X]$. I've tried using the Eisentstein criterion, but I ...
the man's user avatar
  • 2,482
-1 votes
1 answer
87 views

How to factorize the expression $4(ab+cd)^2-\left(a^2+b^2-c^2-d^2\right)^2$? [closed]

Factorise$$4(ab+cd)^2-\left(a^2+b^2-c^2-d^2\right)^2$$ I can't solve this math assignment from my text book. No one knows how to solve it, so I would be so thankful to you if you presented your step-...
Solvex's user avatar
  • 11
-1 votes
1 answer
596 views

An Analogue of CRT for Polynomial Ring

How can we determine the number of factors by CRT? For example, $$\frac{\mathbb{Z}_5[X]}{X^2+1}\cong \frac{\mathbb{Z}_5[X]}{X+2}\times \frac{\mathbb{Z}_5[X]}{X+3},$$ so $\frac{\mathbb{Z}_5[X]}{X^2+...
mallea's user avatar
  • 829
0 votes
1 answer
108 views

prime values polynomial confusing question

The number of prime values of the polynomial $n^3 − 10n^2 − 84n + 840 $ where $n$ is an integer is?? I do not get what they're asking us to do. Is there a specific method to solve this question? I ...
user408113's user avatar
0 votes
1 answer
110 views

Is every polynomial with integer coefficients prime in $\mathbb{Z}[x]$ also prime in $\mathbb{Q}[x]$? [closed]

The question is as in the title: Is every polynomial with integer coefficients prime in $\mathbb{Z}[x]$ also prime in $\mathbb{Q}[x]$?
Julio Yarasca's user avatar