Given the coordinates of any three points on the plane, find the coordinate equations of the two intersecting lines they form.

Answer: Suppose these three points are A(x1, y1), B(x2, y2) and C(x3, y3), then the coordinate equations of the two intersecting lines they form are: straight line AB: y - y1 = (y2 - y1)/(x2 - x1) (x - x1) Line AC: y - y1 = (y3 - y1)/(x3 - x1) (x - x1)