Function Notation is, in most cases, used to replace mapping notation. Under a function, f, the image of an element x in the domain is denoted by f(x). F(x) provides a formula for the function of f, and also represents the value of the function for a given value of x. *With function notation, f(x) does not mean f times x. *The f in F(x) represents the name of the function.

An example of function notation is f(x)=2x + 3. In order to evaluate an equation written in function notation you use the further information given. If you are told to solve f(5) then in your function, you replace all x’s with 5. If you are given f(x) = 13 then you write out the function as so, 13=2x+3 and solve it using isolation from there.