Horizontal Lines• What can you say about the rate of change of a

horizontal line?– It is zero– It is neither increasing or decreasing– Therefore it is called a constant function

• A couple examples are– y = 5– f(x) = -17• What is f(4)?• What is f(-10012)?

Vertical Lines• Is the graph of a vertical line a function? Why or

why not?• It is a set of ordered pairs that satisfy a particular

condition• For example– x = 4– x = -11– Notice they will always have the same x-value

associated with multiple y-values so NOT A FUNCTION