1. **State the problem:** Given the function $f(x) = \frac{x}{x+5}$, find its inverse function $f^{-1}(x)$ and verify that $f^{-1}(f(x)) = f(f^{-1}(x)) = x$.
2. **Find the inverse function:** Start by setting $y = f(x) = \frac{x}{x+5}$.
3. Swap $x$ and $y$ to find the inverse: $x = \frac{y}{y+5}$.
4. Solve for $y$ in terms of $x$:
$$x = \frac{y}{y+5}$$
Multiply both sides by $y+5$:
$$x(y+5) = y$$
$$xy + 5x = y$$
5. Rearrange to isolate $y$:
$$xy - y = -5x$$
$$y(x - 1) = -5x$$
6. Divide both sides by $(x-1)$:
$$y = \frac{-5x}{x - 1}$$
Show the cancellation step:
$$y = \frac{-5x}{\cancel{x - 1}}$$
7. So the inverse function is:
$$f^{-1}(x) = \frac{-5x}{x - 1}$$
8. **Verify $f^{-1}(f(x)) = x$:**
Substitute $f(x)$ into $f^{-1}$:
$$f^{-1}(f(x)) = f^{-1}\left(\frac{x}{x+5}\right) = \frac{-5 \cdot \frac{x}{x+5}}{\frac{x}{x+5} - 1}$$
Simplify denominator:
$$\frac{x}{x+5} - 1 = \frac{x}{x+5} - \frac{x+5}{x+5} = \frac{x - (x+5)}{x+5} = \frac{-5}{x+5}$$
9. Substitute back:
$$f^{-1}(f(x)) = \frac{-5 \cdot \frac{x}{x+5}}{\frac{-5}{x+5}} = \frac{-5x/(x+5)}{-5/(x+5)}$$
10. Simplify the complex fraction:
$$= \frac{-5x}{x+5} \times \frac{x+5}{-5} = x$$
11. **Verify $f(f^{-1}(x)) = x$:**
Substitute $f^{-1}(x)$ into $f$:
$$f(f^{-1}(x)) = f\left(\frac{-5x}{x-1}\right) = \frac{\frac{-5x}{x-1}}{\frac{-5x}{x-1} + 5}$$
12. Simplify denominator:
$$\frac{-5x}{x-1} + 5 = \frac{-5x}{x-1} + \frac{5(x-1)}{x-1} = \frac{-5x + 5(x-1)}{x-1} = \frac{-5x + 5x - 5}{x-1} = \frac{-5}{x-1}$$
13. Substitute back:
$$f(f^{-1}(x)) = \frac{-5x/(x-1)}{-5/(x-1)} = \frac{-5x}{x-1} \times \frac{x-1}{-5} = x$$
14. **Conclusion:** The inverse function is $f^{-1}(x) = \frac{-5x}{x-1}$ and it satisfies $f^{-1}(f(x)) = f(f^{-1}(x)) = x$.
15. **Note on domain:** $f(x)$ is undefined at $x = -5$ (division by zero), and $f^{-1}(x)$ is undefined at $x = 1$.
16. **Table values check:**
- For $x=0$, $f(0) = 0$.
- For $x=10$, $f(10) = \frac{10}{15} = \frac{2}{3}$.
- At $x=-5$, $f(x)$ is undefined.
These match the given table.
Inverse Function D3A3C2
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