Question

Prove that, the points (1, 5), (2, 3) and (-2, -11) are not collinear.

Answer 1

Let the points are A(1, 5), B(2, 3) and C(-2, -11) respectively 

i.e. co-ordinate of A is (1, 5), co-ordinate of B is (2, 3) and co-ordinate of C is (-2, -11).

It is clear that sum of distances of any two sides is not equal to third side. 

So these points are not collinear.