Find the value of λ so that the points (1, – 5), (– 4, 5) and (λ, 7) are collinear.
Given: – (1, – 5), (– 4, 5) and (λ, 7) are collinear
Tip: – For Three points to be collinear, the area of the triangle formed by these points will be zero
Now, we know that,
vertices of a triangle are (x1,y1), (x2,y2) and (x3,y3), then the area of the triangle is given by:
Now,
Substituting given value in above formula
Expanding along R1
⇒
⇒
⇒
⇒ 50 – 10λ = 0
⇒ λ = – 5
⇒