High School

7. If [tex]$x+1$[/tex] is a factor of [tex]$x^3+x^2-16x-16$[/tex], find the remaining factors of the polynomial. Select all that apply.

A. [tex]$x^2-16$[/tex]

B. [tex]$x^2+2x-14$[/tex]

C. [tex]$x-16$[/tex]

D. [tex]$x-4$[/tex]

E. [tex]$x+4$[/tex]

Answer :

To solve the problem of finding the remaining factors of the polynomial [tex]\(x^3 + x^2 - 16x - 16\)[/tex], given that [tex]\(x+1\)[/tex] is a factor, follow these steps:

1. Identify the Polynomial: We are given the polynomial [tex]\(x^3 + x^2 - 16x - 16\)[/tex] and the factor [tex]\(x + 1\)[/tex].

2. Use Polynomial Division: Since [tex]\(x+1\)[/tex] is a factor, we can perform polynomial division of [tex]\(x^3 + x^2 - 16x - 16\)[/tex] by [tex]\(x + 1\)[/tex] to find another factor. When dividing, the remainder should be 0, confirming [tex]\(x + 1\)[/tex] is a factor. The quotient we get is another factor of the polynomial.

3. Calculate the Quotient: The result of the division is [tex]\(x^2 - 16\)[/tex], meaning that the polynomial [tex]\(x^3 + x^2 - 16x - 16\)[/tex] can be expressed as [tex]\((x + 1)(x^2 - 16)\)[/tex].

4. Factor the Quotient Further: We now need to further factor the quotient [tex]\(x^2 - 16\)[/tex]. Recognize that this is a difference of squares:
[tex]\[
x^2 - 16 = (x - 4)(x + 4)
\][/tex]

5. List All Factors: Therefore, the complete factorization of the original polynomial is:
[tex]\[
(x + 1)(x - 4)(x + 4)
\][/tex]

Based on this factorization, the remaining factors of the polynomial [tex]\((x^3 + x^2 - 16x - 16)\)[/tex], after confirming [tex]\(x+1\)[/tex] is a factor, are [tex]\(x - 4\)[/tex] and [tex]\(x + 4\)[/tex].

So, the factors from the given options that apply are:
- D. [tex]\(x-4\)[/tex]
- E. [tex]\(x+4\)[/tex]