1. The problem is to find the inverse function $f^{-1}(x)$ of the function $f(x) = e^{3x + 5}$.
2. To find the inverse, we start by setting $y = f(x)$, so:
$$y = e^{3x + 5}$$
3. The goal is to solve for $x$ in terms of $y$. First, take the natural logarithm (ln) of both sides to undo the exponential:
$$\ln y = \ln \left(e^{3x + 5}\right)$$
4. Using the property $\ln(e^a) = a$, we get:
$$\ln y = 3x + 5$$
5. Now solve for $x$:
$$\ln y - 5 = 3x$$
6. Divide both sides by 3:
$$x = \frac{\cancel{\ln y - 5}}{\cancel{3}}$$
7. Replace $y$ with $x$ to write the inverse function:
$$f^{-1}(x) = \frac{\ln x - 5}{3}$$
8. Therefore, the correct inverse function is:
$$f^{-1}(x) = \frac{\ln x - 5}{3}$$
This matches the first option given.
The other options are incorrect because:
- $\frac{e^x - 5}{3}$ is not the inverse of an exponential function.
- $\frac{\ln x + 5}{3}$ has the wrong sign inside the numerator.
Hence, the answer is $f^{-1}(x) = \frac{\ln x - 5}{3}$.
Inverse Exponential 2C6D79
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