Use the slope formula: (m = frac{y_2 – y_1}{x_2 – x_1})
Choose two points on the line
Subtract the y-values
Subtract the x-values
Divide the change in y by the change in x
Read the slope from the graph as rise over run
Positive slope means the line rises from left to right
Negative slope means the line falls from left to right
Zero slope means the line is horizontal
Undefined slope means the line is vertical