Question
Compute for \( f(x)=\frac{1}{x} \) Homework Help \( \begin{array}{lll}\text { a. } f\left(\frac{1}{2}\right) & \text { b. } f\left(\frac{1}{10}\right) & \text { c. } f(0.01) \\ \text { Solve each of the following quadratic equations. If you need help, refer to the Math Notes box for this lesson. Homework Help } \\ \begin{array}{ll}\text { a. } x^{2}-8 x+15=0 & \text { b. } 2 x^{2}-5 x-6=0\end{array}\end{array} \)
Ask by Lindsey Kelley. in the United States
Jan 22,2025
Real Tutor Solution
Tutor-Verified Answer
Answer
a. \( f\left(\frac{1}{2}\right) = 2 \)
b. \( f\left(\frac{1}{10}\right) = 10 \)
c. \( f(0.01) = 100 \)
---
**Solving Quadratic Equations:**
a. \( x^{2} - 8x + 15 = 0 \)
- Solutions: \( x = 3 \) and \( x = 5 \)
b. \( 2x^{2} - 5x - 6 = 0 \)
- Solutions: \( x = \frac{5 + \sqrt{73}}{4} \) and \( x = \frac{5 - \sqrt{73}}{4} \) (approximately \( x \approx 3.386 \) and \( x \approx -0.886 \))
Solution
Sure, I'd be happy to help you with your homework! Let's tackle each part step by step.
---
## Part 1: Evaluating the Function \( f(x) = \frac{1}{x} \)
### a. Compute \( f\left(\frac{1}{2}\right) \)
\[
f\left(\frac{1}{2}\right) = \frac{1}{\frac{1}{2}} = 2
\]
### b. Compute \( f\left(\frac{1}{10}\right) \)
\[
f\left(\frac{1}{10}\right) = \frac{1}{\frac{1}{10}} = 10
\]
### c. Compute \( f(0.01) \)
\[
f(0.01) = \frac{1}{0.01} = 100
\]
---
## Part 2: Solving Quadratic Equations
### a. Solve \( x^{2} - 8x + 15 = 0 \)
To solve the quadratic equation \( x^{2} - 8x + 15 = 0 \), we can factor it.
1. **Find two numbers that multiply to 15** and **add up to -8**.
The numbers are **-3** and **-5** because:
\[
(-3) \times (-5) = 15 \quad \text{and} \quad (-3) + (-5) = -8
\]
2. **Factor the quadratic:**
\[
x^{2} - 8x + 15 = (x - 3)(x - 5) = 0
\]
3. **Set each factor equal to zero and solve for \( x \):**
\[
x - 3 = 0 \quad \Rightarrow \quad x = 3
\]
\[
x - 5 = 0 \quad \Rightarrow \quad x = 5
\]
**Solutions:** \( x = 3 \) and \( x = 5 \)
---
### b. Solve \( 2x^{2} - 5x - 6 = 0 \)
This quadratic equation doesn't factor neatly, so we'll use the **quadratic formula**:
\[
x = \frac{-b \pm \sqrt{b^{2} - 4ac}}{2a}
\]
Where \( a = 2 \), \( b = -5 \), and \( c = -6 \).
1. **Calculate the discriminant (\( \Delta \)):**
\[
\Delta = b^{2} - 4ac = (-5)^{2} - 4(2)(-6) = 25 + 48 = 73
\]
2. **Apply the quadratic formula:**
\[
x = \frac{-(-5) \pm \sqrt{73}}{2 \times 2} = \frac{5 \pm \sqrt{73}}{4}
\]
3. **Simplify (if necessary):**
The solutions can be left in the exact form:
\[
x = \frac{5 + \sqrt{73}}{4} \quad \text{and} \quad x = \frac{5 - \sqrt{73}}{4}
\]
Alternatively, you can approximate the solutions using a calculator:
\[
\sqrt{73} \approx 8.544
\]
\[
x \approx \frac{5 + 8.544}{4} = \frac{13.544}{4} \approx 3.386
\]
\[
x \approx \frac{5 - 8.544}{4} = \frac{-3.544}{4} \approx -0.886
\]
**Solutions:**
- Exact form: \( x = \frac{5 \pm \sqrt{73}}{4} \)
- Approximate values:
\[
x \approx 3.386 \quad \text{and} \quad x \approx -0.886
\]
---
If you have any more questions or need further clarification, feel free to ask!
Reviewed and approved by the UpStudy tutoring team
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Beyond the Answer
To find \( f(x) = \frac{1}{x} \): - a. \( f\left(\frac{1}{2}\right) = \frac{1}{\frac{1}{2}} = 2 \) - b. \( f\left(\frac{1}{10}\right) = \frac{1}{\frac{1}{10}} = 10 \) - c. \( f(0.01) = \frac{1}{0.01} = 100 \) Now, let's solve those quadratic equations: For \( x^{2}-8x+15=0 \), you can factor it as \( (x-3)(x-5)=0 \), giving \( x=3 \) and \( x=5 \). For \( 2x^{2}-5x-6=0 \), you can apply the quadratic formula or factor. This factors to \( (2x+3)(x-2)=0 \), giving the roots \( x=-\frac{3}{2} \) and \( x=2 \).