Find the value of x for which the points ( x, - 1), (2, 1) and (4, 5) are collinear

Solution:

If points A( x, - 1), B (2, 1) and C (4, 5) are collinear,

Then, Slope of AB = Slope of BC

⇒ [1 - (- 1)]/(2 - x) = (5 - 1)/(4 - 2)

⇒ (1 + 1)/(2 - x) = 4/2

⇒ 2/(2 - x) = 2

⇒ 2 = 4 - 2x

⇒ 2x = 4 - 2

⇒ 2x = 2

⇒ x = 1

Thus, the required value of x = 1

NCERT Solutions Class 11 Maths Chapter 10 Exercise 10.1 Question 8

Find the value of x for which the points ( x, - 1), (2, 1) and (4, 5) are collinear.

Summary:

We found that the value of x is 1 for which the points A( x, - 1), B (2, 1) and C (4, 5) are collinear