Domain - All the x-values (least to greatest) ----Tells the length of your x-axis--- Range - All the y-values (least to greatest) ----Tells the height of your y-axis----

When you are looking at graph and the points are connected - you must determine if the domain repeats.

You determine that by using the vertical line test. You move from left to right across the x-axis. If you have 2 points on the x-value at any point then you DO NOT HAVE A FUNCTION!