Choose two points on the line
Label the points as ((x_1, y_1)) and ((x_2, y_2))
Subtract the y-values: (y_2 – y_1)
Subtract the x-values: (x_2 – x_1)
Divide the change in y by the change in x
Use the slope formula: (m = frac{y_2 – y_1}{x_2 – x_1})
Simplify the fraction if possible
If the line is horizontal, the slope is 0
If the line is vertical, the slope is undefined