Question

find the value of k,if the points (7,-2 ),(5,1)and (3,2k ) are collinear

Answer 1

A(7,-2), B(5,1), C(3,2K)

Δ = 1/2[(x₁y₂+x₂y₃+x₃y₁)-(x₂y₁+x₃y₂+x₁y₃)

Δ = 1/2[(7+10K-6)-(-10+3+14K)] = 1/2[1+10K+7-14K] = 1/2[8-4K] = 4-2K

GIVEN THE POINTS ARE COLLINEAR

Δ = 0

4-2K = 0

2K = 4

K = 2

Answer 2

Hope this will help you