Math
Line Equation From Two Points
Find line equation y = mx + b from two coordinate points.
Frequently Asked Questions
How do I find a line equation from two points?
First find slope: m = (y₂ - y₁) / (x₂ - x₁). Then use point-slope form: y - y₁ = m(x - x₁). Rearrange to y = mx + b to find b-intercept.
What is point-slope form?
y - y₁ = m(x - x₁) where (x₁, y₁) is a known point and m is slope. Convert to slope-intercept by solving for y.
How do I find the y-intercept?
Substitute m and either point into y = mx + b, then solve for b.
What if the two points have the same x-coordinate?
The line is vertical (undefined slope). Equation is x = constant.
What if the two points are the same?
Cannot determine a unique line. Need two distinct points.