Question

The points (-5, 1), (1, p) and (4, -2) are collinear if the value of p is ______.

Options

• 3

• 2

• 1

• - 1

Answer 1

The points (-5, 1), (1, p) and (4, -2) are collinear if the value of p is -1.

Explanation:

The points are collinear if area of Δ = 0

`= 1/2 [- 5("p" + 2) + 1(-2 - 1) + 4(1 - "p")] - 0`

⇒ -5 p - 10 - 3 + 4 - 4p = 0

⇒ - 9p = + 9

∴ p = - 1