Formula
$$ \dfrac{y-y_1}{y-y_2} = \dfrac{x-x_1}{x-x_2}$$
Variables
A(x1,y1)
→
First point on a line
B(x2, y2)
→
Seconf point on a line
$$ \dfrac{y-y_1}{y-y_2} = \dfrac{x-x_1}{x-x_2}$$