Function notation

Math

Definition

A way of writing functions using the format f(x) to name the function and show the input variable. f(x) is read as 'f of x' and represents the output value when x is the input.

Examples

  • If f(x) = 2x + 3, then f(4) = 2(4) + 3 = 11
  • g(x) = x² means g(−3) = 9
  • A phone plan cost function C(m) = 30 + 0.10m where m is minutes used
Key Fact

f(x) does NOT mean f times x; it means the output of function f for input x.

Related Terms

Domain and range Composition of functions Inverse functions Evaluating expressions

Study This Concept

Practice function notation with free review games in these units:

Algebra 2 Unit 2: Linear Functions and Systems