On a graph called the coordinate plane, there are two axis. The horizontal axis is the x-axis and is known as the independent variable. A great example of an independent variable is time. Time is always represented on the x-axis because time passes by. It does not depend on anything.
The other axis is the y-axis. It is the vertical axis on the graph. It is called the dependent variable because its value depends on x. For example, if you were looking at miles per hour, the number of miles would depend on how many hours you traveled. You have to know the time to find miles. This is a dependent variable.
