The document discusses how to calculate the slope of a line given two points on the line. It provides two methods:
1) The slope formula, which is the rise over the run between two points (change in y over change in x).
2) The algebraic method, where the slope m is calculated as (y2 - y1) / (x2 - x1).
It also notes that horizontal lines have a slope of 0, and vertical lines have undefined slopes.