The document discusses inverse functions and how to find them. It provides examples of inverse pairs of functions and explains that for functions f and g to be inverses, f(g(x)) = x and g(f(x)) = x. It also notes that the horizontal line test determines whether the inverse of a function is itself a function. The document shows how to take a function, find its inverse by swapping x and y and solving for y, and provides examples of doing this for various functions.