Mistake in the question; The slope of the line is -2/3.
To count the slope of the graph from any point on the graph; He counts down 2 then right 3 to end up on the line again.
The slope of a linear graph refers to the change behaviour of its dependent variable (usually y-axis) with respect to its Independent variable (usually x-axis).
In essence;
slope, m = (y2-y1)/(x2-x1)
Consequently, From any point on the graph, he counts down 2 then right 3 to end up on the line again.
