Coordinate Geometry Question 22
Question: If the points $ (-5,1),(p,5) $ and $ (10,7) $ are collinear, then the value of p will be
[MP PET 1984]
Options:
A) 5
B) 3
C) 4
D) 7
Show Answer
Answer:
Correct Answer: A
Solution:
$ \frac{1}{2} \begin{vmatrix} -5 & 1 & 1 \\ p & 5 & 1 \\ 10 & 7 & 1 \\ \end{vmatrix} |=0\Rightarrow \begin{vmatrix} -5 & 1 & 1 \\ p & 5 & 1 \\ 10 & 7 & 1 \\ \end{vmatrix} =0 $
$ \Rightarrow 10-(p-10)+(7p-50)=0\Rightarrow p=5 $ .
BETA
