Answer
The interchanging of $x$ and $y$ make sense since the functions used are one-to-one functions.
Work Step by Step
By definition, the inverse function is found by switching the coordinates of the inputs and the outputs.
Example: We have the points $(1,2)$, $(3,4)$, and $(5,6)$. This is a one-to-one function, so we can find the inverse equation by swapping the inputs and the outputs. Thus, we would have the points $(2,1)$, $(4,3)$, and $(6,5)$ for the inverse function.