Start by solving for $x$.
$y =\operatorname{log}_3x$
$x = 3^y$
Now 'rename the $x$ and $y'$.

$f^{ −1}(x) = 3^x$

$y = 6^{2x}$
$2x =\operatorname{log}_6y$
$x=\frac{\text{log}_6y}{2}$
$f^{−1}(x) =$ ____________

Notice that $y = π^²$ is a horizontal line. What is the inverse of a horizontal line?

Refer to hint in part (b).

Before you convert to a logarithm, subtract $k$ from both sides.