Functions are written in function notation with the name of the function ... (11) = 2 \times 11 + 3 = 25\) Inverse functions. A function links an input value to an output value.

Algebraic formulae - Eduqas Function notation ... = 3 \times 3 - 1 = 8\) Composite functions. Composite functions are made when the output from one function is used as the input of another function.