Functions are often represented as equations. Function notation identifies the independent variable in the equation.

The equation of the function T(n) = 7n is expressed in function notation. This function can be read as "T of n equals 7 times n" or simply "T of n equals 7n". Using this notation, n represents the input and T(n) represents the output.

 

Example 3

Sally is planning her sweet sixteen birthday celebration. She wants to watch the new Jim Banter secret agent movie with 20 of her closest friends and family members. Tickets cost $9.00 each. Express the total cost, T, as a function of the number of tickets purchased, n, and then determine how much Sally needs to spend in total for all 21 tickets.

Function: T(n) = 9n

T(n) = 9n
n = 21 tickets
T(21) = 9(21)
T(21) = 189


Sally will need to spend $189.00 for 21 tickets to the movie.