Finding the Equation of a Line from Two Points
To find the equation of a line from two points, use the point-slope form:
y - y1 = m(x - x1)
Steps:
- 1. Find the slope (
m): - 2. Plug in one point:
- 3. Simplify (optional):
- Find the slope:
- Use point-slope form with (2, 3):
- Simplify:
- Find slope with
m = (y₂ - y₁)/(x₂ - x₁)and plug into point-slope form. - Final equation can be left in point-slope or converted to slope-intercept form.
For points (x₁, y₁) and (x₂, y₂),
m = (y₂ - y₁) / (x₂ - x₁)
Use either point as (x₁, y₁) and your calculated m.
You can rearrange to slope-intercept form: y = mx + b.
Example:
Given points (2, 3) and (4, 7):
m = (7 - 3) / (4 - 2) = 4 / 2 = 2
y - 3 = 2(x - 2)
y - 3 = 2x - 4
y = 2x - 1
Takeaways: