Show that the following points are collinear:

A(2, – 2), B(–3, 8) and C(–1, 4)

To show that the points are collinear, we show that the area of triangle is equilateral = 0


Given, the area of the triangle, Δ = 0


Δ = 1/2(x1(y2−y3) + x2(y3−y1) + x3(y1−y2))


Δ = 1/2{2 (8– 4) + (–3) (4 + 2) –1 (2– 8)}


Δ = 1/2 {8–18 + 10}


Δ = 0


Hence the points A(2, – 2), B(–3, 8) and C(–1, 4) are collinear.


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