Slope Between Two Points
Rise over run, undefined vertical lines, and the point-slope line through a known point.
| Name | Formula | Note |
|---|---|---|
| Two-point slope |
m = (y₂ − y₁) / (x₂ − x₁)
x₂ ≠ x₁. Same units on each axis. |
x₂ ≠ x₁. Same units on each axis. |
| Horizontal line |
m = 0
y₂ = y₁ and the points are distinct. |
y₂ = y₁ and the points are distinct. |
| Vertical line |
x₂ = x₁
Slope is undefined; do not divide by zero. |
Slope is undefined; do not divide by zero. |
| Point-slope form |
y − y₁ = m(x − x₁)
A line through (x₁, y₁) with slope m. |
A line through (x₁, y₁) with slope m. |
| Slope-intercept |
y = mx + b
b is the y-intercept when the line crosses x = 0. |
b is the y-intercept when the line crosses x = 0. |