Westonci.ca is the ultimate Q&A platform, offering detailed and reliable answers from a knowledgeable community. Join our platform to connect with experts ready to provide detailed answers to your questions in various areas. Experience the convenience of finding accurate answers to your questions from knowledgeable experts on our platform.

If a polynomial function [tex]\( f(x) \)[/tex] has roots -9 and [tex]\( 7-i \)[/tex], what must be a factor of [tex]\( f(x) \)[/tex]?

A. [tex]\( (x - (7+i)) \)[/tex]

B. [tex]\( (x + 9) \)[/tex]

C. [tex]\( (x - (7-i)) \)[/tex]

D. [tex]\( (x + (7+i)) \)[/tex]

Sagot :

Certainly! Let's solve this step-by-step.

When you are given the roots of a polynomial, you know that the factors of the polynomial correspond to [tex]\((x - \text{root})\)[/tex].

Given roots:
1. [tex]\(-9\)[/tex]
2. [tex]\(7 - i\)[/tex]

### Step 1: Discovering All Roots

Since the function has complex roots, and complex roots of polynomials with real coefficients come in conjugate pairs, the third root must be the conjugate of [tex]\(7 - i\)[/tex], which is [tex]\(7 + i\)[/tex].

So, the roots are:
- [tex]\(-9\)[/tex]
- [tex]\(7 - i\)[/tex]
- [tex]\(7 + i\)[/tex]

### Step 2: Writing Corresponding Factors

Each root [tex]\(r\)[/tex] corresponds to a factor of the form [tex]\((x - r)\)[/tex]. Therefore, the factors of the polynomial are:
- [tex]\((x - (-9)) = (x + 9)\)[/tex]
- [tex]\((x - (7 - i)) = (x - 7 + i)\)[/tex]
- [tex]\((x - (7 + i)) = (x - 7 - i)\)[/tex]

### Step 3: Identifying the Given Options

Now, let's match the options with the factors we have derived:

1. [tex]\((x - (7 + i))\)[/tex]: This directly matches one of the factors we identified.
2. [tex]\((x - (-7-1))\)[/tex]: This doesn't match any of our identified factors.
3. [tex]\((x + (7 + i))\)[/tex]: This also doesn't match any of our identified factors.
4. [tex]\((x + (7 - i))\)[/tex]: This isn't a match either.

### Conclusion

The correct factor of the polynomial [tex]\(f(x)\)[/tex] that matches one of the given roots must be:
[tex]\[ (x - (7 + i)) \][/tex]

Hence the correct factor is:
[tex]\[ (x - (7 + i)) \][/tex]