Question

The value of P for which the points (–5, 1), (1, –1) and (P, –2) are collinear, is

• A. 4
• B. 2
• C. 3
• D. 1

Answer 1

The correct option is A 4

Points (–5, 1), (1, –1), (P, –2) are collinear.

Therefore, the area of triangle formed using these points is zero.

$\Rightarrow \frac{1}{2}|-5(-1+2)+1(-2-1)+P(1+1\left)\right|=0$

$\Rightarrow |-5-3+2P|=0$

$\Rightarrow P=4$

Hence, the correct answer is option (a)