Answer
$C(x)$=the cost of making $x$ units.
$C^{-1}(x)$=the number of units made for a cost of $x$.
Work Step by Step
The function $C(x)$ represents the cost of manufacturing $x$ T-shirts.
The function $C^{-1}(x)$ represents the number of T-shirts that can be manufactured for a cost $x$.