A) \[0\]
B) \[1\]
C) \[2\]
D) None of these
Correct Answer: D
Solution :
Since, given vectors are coplanar. \[\therefore \] \[a\,.\,(b\times c)=0\] \[\Rightarrow \] \[\left| \begin{matrix} 1 & 4 & -7 \\ \lambda & -1 & 4 \\ -9 & 0 & 18 \\ \end{matrix} \right|=0\] Expanding along \[{{C}_{1}},\] we get \[1(-18-0)-\lambda (72-0)-9(16-7)=0\] \[\Rightarrow \] \[-18-72\lambda -81=0\] \[\Rightarrow \] \[72\lambda =-99\] \[\Rightarrow \] \[\lambda =\frac{-11}{8}\]You need to login to perform this action.
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