Use the formula: m = (y₂ – y₁) / (x₂ – x₁)
Identify two points: (x₁, y₁) and (x₂, y₂)
Subtract the y-values: y₂ – y₁
Subtract the x-values: x₂ – x₁
Divide the change in y by the change in x
From a graph, use: slope = rise / run
From an equation in slope-intercept form, use: y = mx + b
The slope is the value of m
A positive slope rises from left to right
A negative slope falls from left to right
A horizontal line has a slope of 0
A vertical line has an undefined slope