Answer
$f^{-1}(x)=\frac{x}{12}$
Work Step by Step
Equation given:
$f(x) = 12x$
Replace $f(x)$ with $y$:
$y = 12x$
Make x the subject:
$\frac{y}{12} = x$
Interchange x and y:
$\frac{x}{12} = y$
Thus the inverse function is:
$f^{-1}(x)=\frac{x}{12}$