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 7 P + 34 - 6 = 0 7 P + 28 = 0 7 P = - 28 \[P=-\frac{28}{7}=-4\]You need to login to perform this action.
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