Question

2) The points (-5, 1), (1, p) and (4, -2) are collinear if the value of p is (a) 3 (b) 2 (c) 1 (d) -1​

Answer 1

Answer:

the answer is -1

Step-by-step explanation:

The given points are A(−5,1), B(1,p) and C(4,−2)

We have (x

1

=−5,y

1

=1),(x

2

=1,y

2

=p) and (x

3

=4,y

3

=−2)

The given points A,B and C are collinear

Therefore, x

1

(y

2

−y

3

)+x

2

(y

3

−y

1

)+x

3

(y

1

−y

2

)=0

⇒(−5)⋅(p+2)+1⋅(−2−1)+4⋅(1−p)=0

⇒(−5p−10−3+4−4p)=0

⇒−9p=−9

⇒p=−1

Hence, p=−1