How can the function notation fx be rewritten as?

The function notation ( f(x) ) can be rewritten in various ways, depending on the context. It can be expressed as ( y ) if you're simply referring to the output of the function. Alternatively, it can be represented in a different format such as ( g(x) ) if a different function is being defined, or in terms of a specific variable, like ( z ) in the context of a transformation, as in ( z = f(x) ).