Step-by-step explanation:
We remeber that If we compose a function and it's inverse,

A invertible function is one to one so suppose that we have two inverse, g(x) and h(x). Let plug them in ,

and

Since f is a invertible function, it is one to one so if g and h are both inverse of f, then they are eqaul


Thus, a invertible function can have only one inverse.