Pick two points on the line: ((x_1, y_1)) and ((x_2, y_2))
Use the slope formula: (m = frac{y_2 – y_1}{x_2 – x_1})
Subtract the y-values to find the rise
Subtract the x-values to find the run
Divide the rise by the run
If the line is horizontal, the slope is (0)
If the line is vertical, the slope is undefined