Use Formal Function Notation

A function is a rule that connects inputs and outputs.

Every input has one corresponding value as an output.

f(x) means a function of x, where x is a specific input.

f(x) = x² + 3 means a functions of x where you square x and then add 3 to it.

If you want to work out the output when the input is 3, we write it like this:

f(3)= 3² + 3 = 9 + 3 = 12

Sometimes the input is an algebraic term.

If this is the case, replace each letter x with the desired input.

Let's write the function written above f(x) = x² + 3 as a function with input 4x:

f(4x) = (4x)² + 3 = 16x² + 3

In this activity, we will use formal notation (shown in the examples above) to express and calculate inputs and outputs of functions.