Question

In each of the following find the value of 'k', for which the points are collinear.

(7, -2), (5, 1), (3, -k) 

Answer 1

For collinear points, area of triangle formed by them is zero.

Therefore, for points (7, -2) (5, 1), and (3, k), area = 0

`1/2 [7 { 1- k} + 5(k-(-2)) + 3{(-2) + 1}] = 0`

7 - 7k + 5k +10 -9 = 0

-2k + 8 = 0

k = 4