College

Select the correct answer.

Which expression is a prime polynomial?

A. [tex]x^4 + 20x^2 - 100[/tex]

B. [tex]3x^2 + 18y[/tex]

C. [tex]x^3 - 27y^6[/tex]

D. [tex]10x^4 - 5x^3 + 70x^2 + 3x[/tex]

Answer :

To determine which expression is a prime polynomial, let's examine each option to see if they can be factored into simpler polynomials. A prime polynomial is one that cannot be factored into polynomials of lower degree with integer coefficients.

Option A: [tex]\(x^4 + 20x^2 - 100\)[/tex]

Let's see if this polynomial can be factored:

- Break down the expression:
- [tex]\(x^4 + 20x^2 - 100\)[/tex] can be written in terms of quadratic form as [tex]\((x^2)^2 + 20(x^2) - 100\)[/tex].
- This can potentially factor as [tex]\((x^2 - 10)(x^2 + 10)\)[/tex].

Since it can be factored, it's not a prime polynomial.

Option B: [tex]\(3x^2 + 18y\)[/tex]

Let's check if it's factorable:

- Notice that both terms share a common factor of 3:
- Factoring out the 3 gives us: [tex]\(3(x^2 + 6y)\)[/tex].

Since it can be factored, this is not a prime polynomial.

Option C: [tex]\(x^3 - 27y^6\)[/tex]

Let's examine its factorability:

- Recognize this as a difference of cubes:
- The expression can be rewritten as [tex]\((x)^3 - (3y^2)^3\)[/tex].
- The difference of cubes formula is [tex]\(a^3 - b^3 = (a-b)(a^2+ab+b^2)\)[/tex].
- Applying the formula gives us: [tex]\((x - 3y^2)(x^2 + 3xy^2 + 9y^4)\)[/tex].

Since this can be factored, it’s not a prime polynomial.

Option D: [tex]\(10x^4 - 5x^3 + 70x^2 + 3x\)[/tex]

Let's review its factorability:

- Note that every term has an [tex]\(x\)[/tex] and can be factored by extracting the greatest common factor:
- Factoring out [tex]\(x\)[/tex] yields: [tex]\(x(10x^3 - 5x^2 + 70x + 3)\)[/tex].

Since it can be factored, it's not a prime polynomial.

Conclusion:

Each option can be factored, meaning none of these expressions is a prime polynomial. Thus, none of the options provided is a prime polynomial.