Point-Slope Form

If you know the slope m of a line and the coordinates (x₁, y₁) of one point on the line, you can write the equation of the line in point-slope form.

y – y₁ = m(x – x₁)

Here, m = –1/2, x₁ = –3, and y₁ = 2, so the equation is:

or

Slope-intercept form is a special case of point-slope form, where we use the y-intercept coordinate (0, b) as our point.