Final answer:
An equation f(4)=16 means that when the input value is 4, the output value is 16.
Step-by-step explanation:
An equation in the form f(4)=16 means that when the input value of the function f is 4, the output value is 16.
For example, if f represents the function that multiplies an input by 4, then f(4)=16 because 4 multiplied by 4 equals 16.
In terms of input and output values, f(4)=16 means that when the input value is 4, the function will return an output value of 16.