Given: – (3, 1) and (9, 3) are collinear points

Tip: – For Three points to be collinear, the area of triangle formed by these points will be zero

Now, we know that,

Vertices of a triangle are (x₁,y₁), (x₂,y₂) and (x₃,y₃), then the area of the triangle is given by:

Now,

Let, 3^rd point be (x,y)

Substituting given value in above formula

⇒

Expanding along R₁

⇒

⇒ [x(– 2) – y(– 6) + 1(0)] = 0

⇒ – 2x + 6y = 0

⇒ x – 3y = 0

It’s the equation of line