Figure 6.9 illustrates the rise and run of a line you generate with a linear equation. To identify the slope, consider first that you can identify a line using two points.
In Figure 6.9, you create three lines using unique sets of coordinates. Each line starts at the origin of the Cartesian plane. For the middle line, the coordinate set is as follows:
(0, 0) (2, 2)
Given this set of coordinates, you can then determine the slope of the line if you establish the ratio of the rise (y) to the run (x). Here is the equation and work that accomplishes this ...