Answer:
Both the equation and its inverse are functions.
Explanation:
In order to solve this problem lets first find the inverse of this function. This is done below:

We first swap x and y.

We now isolate y.

Functions are relations between two groups of numbers, in such a way that one number on the input group must generate a singular answer from the output group. This holds true for both f(x) and its inverse, therefore both are functions.