Question

find the value of k if the point A(8, 1) B(K,- 4) and C (2,-5 )are collinear

Answer 1

Answer:

Step-by-step explanation:

If the points are collinear .

Therefore, Area of ∆ ABC = 0

1/2{x1(y2-y3) + x2(y3-y1) + x3(y1-y2)} = 0

where, x1= 8, x2=K, x3= 2

And y1=1, y2= -4, y3=-5

Putting all the value in Area of ∆ ABC

1/2{8(-4+5)+K(-5-1)+2(1+4)}= 0

1/2{8(1)+K(-6)+2(5)}= 0

{8-6K+10}= 0

-6K+18= 0

-6K= -18

K= 3