The function $f(x) = \frac{9x + 8}{x - 7}$ is one-to-one.
a. Find an equation for $f^{-1}(x)$, the inverse function.
b. Verify that your equation is correct by showing that $f(f^{-1}(x)) = x$ and $f^{-1}(f(x)) = x$.
a. Select the correct choice below and fill in the answer box(es) to complete your choice.
(Simplify your answers. Use integers or fractions for any numbers in the expression.)
A. $f^{-1}(x) = \Box$, for $x \ge \Box$
B. $f^{-1}(x) = \Box$, for all x
C. $f^{-1}(x) = \Box$, for $x \ne \Box$
D. $f^{-1}(x) = \Box$, for $x \le \Box$