Simplify the following inverse: \[ f\left(f^{-1}(x)\right)=[?] \]

When you take the inverse function \( f^{-1} \) of a function \( f \) and then apply the function \( f \) to it, essentially you are reversing the operation. This means that applying \( f \) to its inverse will yield the original input \( x \). So, \( f\left(f^{-1}(x)\right) = x \). In simpler terms, the function takes back the value that was originally fed into it, demonstrating the beautiful symmetry of functions and their inverses.