A) - 2
B) 0
C) 1
D) 7
Correct Answer: D
Solution :
Let \[A=\left[ \,\begin{matrix} 1 & 2 & -3 \\ 0 & 1 & 2 \\ 0 & 0 & 1 \\ \end{matrix}\, \right]\] Þ |A| = 1 \[adj\,(A)={{\left[ \begin{matrix} 1 & 2\,\,\, & -1 \\ -2 & 1 & 1 \\ 7\,\, & -2 & 1 \\ \end{matrix} \right]}^{T}}\]. Hence, \[{{A}^{-1}}=\frac{adj\,(A)}{|A|}\] Þ \[{{A}^{-1}}=\left[ \begin{matrix} 1 & -2 & 7 \\ 2 & 1 & -2 \\ -1 & 1 & 1 \\ \end{matrix} \right]\] . Hence, element\[z=3\].You need to login to perform this action.
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