The slope of a line can be found, given two points, as follows:
[tex]P_{1}(-5.5,6.1) \\ \\ P_{2}(-2.5,3.1) \\ \\ m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}} \\ \\ m=\frac{3.1-6.1}{-2.5-(-5.5)}=-1[/tex]
So this slope tells us the direction of a line and represents the vertical change divided by the horizontal change.
