Evaluating Functions in math

Two examples of function notation are the following:

• f(x)  = 2x
• h(x) =  x²

To evaluate a function, we insert a given x value, a number in the domain, and see what number we get, which is a number in a range.  Some examples:
The two functions below refer to functions listed up above.

• To evaluate f(4)   f(4) = 2(4) = 8 We just evaluated f(x) for the value x = 4.
• evaluate h(-2) (-2)² = 4