Question

If the three points A(h, k), B(x₁, y₁) and C(x₂, y₂) lie on a line then show that (h – x₁)(y₂ – y₁) = (k – y₁)(x₂ – x).

Answer 1

For the lines to be in a line, the slope of the adjacent lines should be the same.

Given points are A(h,k),B(x₁,y₁) and C(x₂,y₂)

So slope of AB = BC = CA

Hence proved.