Use the slope formula: (m = frac{y_2 – y_1}{x_2 – x_1})
Identify two points on the line: ((x_1, y_1)) and ((x_2, y_2))
Subtract the y-values
Subtract the x-values
Divide the change in y by the change in x
Simplify the fraction if needed
For a graph, count rise over run
For a horizontal line, the slope is 0
For a vertical line, the slope is undefined
