A) 16
B) -4
C) 4
D) -8
Correct Answer: B
Solution :
For coplanarity \[\left| \begin{matrix} 2 & -1 & 1 \\ 1 & 2 & -3 \\ 3 & P & 5 \\ \end{matrix} \right|=0\] \[2(10+3P)+1(5\,+\,9)+1(P-6)=0\] \[20+6P+5+9+P-6=0\] \[7P+34-6=0\] \[7P+28=0\] \[7P=-28\] \[P=-\frac{28}{7}=-4\]You need to login to perform this action.
You will be redirected in
3 sec