Question

Find the value of k for which the points are collinear.
(i). (7,-2) (5,1). (3,k).
(ii) (8,1) (k,-4) (2,-5).

Answer 1

when they are collinear then slopes are equal

I) 1+2/5-7 = k-1/3-5

3/-2 = k-1/-2

k-1 = 3 => k = 4

II) -4-1/k-8 = -5-1/2-8

-5/k-8 = -6/-6 = 1

k-8 =-5 => k = 3

Hope it helps u :-)