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