Question
Select the inverse of each function. a. \( f(x)=-3 x-12 \) \[ \begin{array}{l}\text { A) } f^{-1}(x)=-3 x+36 \\ \text { B) } f^{-1}(x)=-\frac{1}{3} x-4 \\ \text { C) } f^{-1}(x)=-4 x-\frac{1}{3} \\ \text { D) } f^{-1}(x)=3 x+12\end{array} \] Part B b. \( g(x)=\frac{1}{3} x-12 \)
Ask by Patel Rose. in the United States
Feb 20,2025
Upstudy AI Solution
Tutor-Verified Answer
Answer
The inverse of \( f(x) = -3x - 12 \) is \( f^{-1}(x) = -\frac{x + 12}{3} \), and the inverse of \( g(x) = \frac{1}{3}x - 12 \) is \( g^{-1}(x) = 3x + 36 \).
Solution
Function by following steps:
- step0: Find the inverse:
\(f\left(x\right)=-3x-12\)
- step1: Replace \(f\left(x\right)\) with \(y:\)
\(y=-3x-12\)
- step2: Interchange the variables:
\(x=-3y-12\)
- step3: Swap the sides:
\(-3y-12=x\)
- step4: Move the constant to the right side:
\(-3y=x+12\)
- step5: Change the signs:
\(3y=-x-12\)
- step6: Divide both sides:
\(\frac{3y}{3}=\frac{-x-12}{3}\)
- step7: Divide the numbers:
\(y=-\frac{x+12}{3}\)
- step8: Replace \(y\) with \(f^{-1}\left(x\right):\)
\(f^{-1}\left(x\right) = -\frac{x+12}{3}\)
Find the inverse of the function \( g(x)=\frac{1}{3} x-12 \)
Function by following steps:
- step0: Find the inverse:
\(g\left(x\right)=\frac{1}{3}x-12\)
- step1: Replace \(g\left(x\right)\) with \(y:\)
\(y=\frac{1}{3}x-12\)
- step2: Interchange the variables:
\(x=\frac{1}{3}y-12\)
- step3: Swap the sides:
\(\frac{1}{3}y-12=x\)
- step4: Move the constant to the right side:
\(\frac{1}{3}y=x+12\)
- step5: Multiply by the reciprocal:
\(\frac{1}{3}y\times 3=\left(x+12\right)\times 3\)
- step6: Multiply:
\(y=3x+36\)
- step7: Replace \(y\) with \(g^{-1}\left(x\right):\)
\(g^{-1}\left(x\right) = 3x+36\)
Let's find the inverses of the given functions step by step.
### Part A: Finding the Inverse of \( f(x) = -3x - 12 \)
1. **Set the function equal to \( y \)**:
\[
y = -3x - 12
\]
2. **Swap \( x \) and \( y \)**:
\[
x = -3y - 12
\]
3. **Solve for \( y \)**:
\[
x + 12 = -3y
\]
\[
y = -\frac{x + 12}{3}
\]
Thus, the inverse function is:
\[
f^{-1}(x) = -\frac{x + 12}{3}
\]
Now, let's check the options provided:
- A) \( f^{-1}(x) = -3x + 36 \)
- B) \( f^{-1}(x) = -\frac{1}{3}x - 4 \)
- C) \( f^{-1}(x) = -4x - \frac{1}{3} \)
- D) \( f^{-1}(x) = 3x + 12 \)
None of the options match the calculated inverse \( f^{-1}(x) = -\frac{x + 12}{3} \).
### Part B: Finding the Inverse of \( g(x) = \frac{1}{3}x - 12 \)
1. **Set the function equal to \( y \)**:
\[
y = \frac{1}{3}x - 12
\]
2. **Swap \( x \) and \( y \)**:
\[
x = \frac{1}{3}y - 12
\]
3. **Solve for \( y \)**:
\[
x + 12 = \frac{1}{3}y
\]
\[
y = 3(x + 12)
\]
\[
y = 3x + 36
\]
Thus, the inverse function is:
\[
g^{-1}(x) = 3x + 36
\]
In summary:
- The inverse of \( f(x) = -3x - 12 \) is \( f^{-1}(x) = -\frac{x + 12}{3} \) (not listed in the options).
- The inverse of \( g(x) = \frac{1}{3}x - 12 \) is \( g^{-1}(x) = 3x + 36 \).
Answered by UpStudy AI and reviewed by a Professional Tutor
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Beyond the Answer
To find the inverse of the function \( f(x) = -3x - 12 \), start by switching \( x \) and \( y \), giving you \( x = -3y - 12 \). Rearranging this equation to solve for \( y \) leads to \( y = -\frac{1}{3}x - 4 \). So, the correct inverse is option B) \( f^{-1}(x) = -\frac{1}{3}x - 4 \). For the function \( g(x) = \frac{1}{3}x - 12 \), we again switch \( x \) and \( y \) to obtain \( x = \frac{1}{3}y - 12 \). Rearranging to isolate \( y \) gives us \( y = 3x + 36 \). Thus, the inverse function is \( g^{-1}(x) = 3x + 36 \).