Question
What are the zeros of the given rational function below? \( f(x)=\frac{-x^{2}+16 x-63}{x^{2}-2 x-35} \) \( x=9 \) and \( x=5 \) \( x=9 \) only \( x=5 \) only No zeros possible for this function
Ask by Osborne Gibson. in the United States
Jan 25,2025
Real Tutor Solution
Tutor-Verified Answer
Answer
The only zero of the function is \( x = 9 \).
Solution
To determine the zeros of the rational function \( f(x) = \frac{-x^{2} + 16x - 63}{x^{2} - 2x - 35} \), follow these steps:
1. **Find the Zeros of the Numerator:**
Zeros occur where the numerator is equal to zero.
\[
-x^{2} + 16x - 63 = 0
\]
Multiply both sides by \(-1\) to simplify:
\[
x^{2} - 16x + 63 = 0
\]
Factor the quadratic:
\[
(x - 9)(x - 7) = 0
\]
Therefore, the potential zeros are \( x = 9 \) and \( x = 7 \).
2. **Check the Denominator for Restrictions:**
The denominator cannot be zero, as this would make the function undefined.
\[
x^{2} - 2x - 35 = 0
\]
Factor the quadratic:
\[
(x - 7)(x + 5) = 0
\]
So, \( x = 7 \) and \( x = -5 \) are not in the domain of \( f(x) \).
3. **Determine the Valid Zeros:**
- \( x = 9 \) is a valid zero since it does not make the denominator zero.
- \( x = 7 \) is **not** a valid zero because it makes the denominator zero, resulting in an undefined value.
**Conclusion:**
The only zero of the function is \( x = 9 \).
**Answer:**
\( x=9 \) only
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Mind Expander
To find the zeros of the rational function \( f(x) = \frac{-x^{2} + 16x - 63}{x^{2} - 2x - 35} \), we focus on the numerator. Setting it equal to zero gives us the equation \(-x^{2} + 16x - 63 = 0\). Factoring, we get \(-(x - 9)(x - 7) = 0\), leading to \( x = 9 \) and \( x = 7 \) as the zeros of the function. Now, to evaluate \( f(x) \), we need to ensure the denominator isn't zero at these points. The denominator is \( x^{2} - 2x - 35 \), which factors to \( (x - 7)(x + 5) \). Thus, at \( x = 7 \), the function is undefined, making \( x = 9 \) the only valid zero.