If $A=\left[\begin{array}{ccc}1 & 0 & 2 \ -1 & 1 & -2 \ 0 & 2 & 1\end{array} ight]$, adj $A=\left[\begin{array}{ccc}5 & x & -2 \ 1 & 1 & 0 \ -2 & -2 & y\end{array} ight]$, then value of $\mathrm{x}+\mathrm{y}$ is

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If $A=\left[\begin{array}{ccc}1 & 0 & 2 \ -1 & 1 & -2 \ 0 & 2 & 1\end{array}ight]$, adj $A=\left[\begin{array}{ccc}5 & x & -2 \ 1 & 1 & 0 \ -2 & -2 & y\end{array}ight]$, then value of $\mathrm{x}+\mathrm{y}$ is

Aicharya · Accepted Answer

$x$ is element $a_{12}$ in adj (A) $	herefore \mathrm{x}=$ cofactor of $\mathrm{a}_{21}=(-1)^{2+1}\left|\begin{array}{ll}0 & 2 \ 2 & 1\end{array}ight|=-(-4)=4$ Similarly, $y=(-1)^{3+3}\left|\begin{array}{cc}1 & 0 \ -1 & 1\end{array}ight|=1 \Rightarrow x+y=5$

If $A=\left[\begin{array}{ccc}1 & 0 & 2 \\ -1 & 1 & -2 \\ 0 & 2 & 1\end{array}\right]$, adj…

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