the line segment joining the points A ( 2 , 1 ) B ( 5 , -8 ) is trisected at the points p and q such that P is nearer to A . if P also lies on the line given by 2 x - y + k =0 , find the value of k.
The given point are A(2, 1) and B(5, – 8).
Given, P and Q trisects the line segment AB.
∴ AP = PQ = QB
PB = PQ + QB = AP + AP = 2AP
AP : PB = AP : 2AP = 1 : 2
∴ P divides the line segment AB in the ration 1 : 2.
∴ Coordinates of P
P(3, – 2) lies on 2x – y + k = 0.
∴ 2 × 3 – (– 2) + k = 0
⇒ 6 + 2 + k = 0
⇒ 8 + k = 0
⇒ k = – 8
Thus, the value of k is – 8.