78787 If \(A=\left[\begin{array}{lll}1 & 2 & 1 \\ 2 & 1 & 0\end{array}\right], B=\left[\begin{array}{ll}1 & 2 \\ 2 & 1 \\ 0 & 1\end{array}\right]\), then \((A B)^{-1}\) is

78788 If \(A=\left[\begin{array}{ll}1 & 1 \\ 1 & 2\end{array}\right], B=\left[\begin{array}{ll}4 & 1 \\ 3 & 1\end{array}\right]\), then \((A+B)^{-1}=\)

78789 If \(\mathrm{AX}=\mathrm{B}\), where \(\mathrm{A}=\left[\begin{array}{ccc}1 & -1 & 1 \\ 2 & -1 & 0 \\ 3 & 3 & -4\end{array}\right], \mathrm{B}=\left[\begin{array}{l}1 \\ 1 \\ 2\end{array}\right]\)
and \(X=\left[\begin{array}{l}x \\ y \\ z\end{array}\right]\), then \(x+y+z=\)

78790 If \(A=\left[\begin{array}{ccc}0 & -1 & 0 \\ -1 & 0 & 0\end{array}\right]\), then

78787 If \(A=\left[\begin{array}{lll}1 & 2 & 1 \\ 2 & 1 & 0\end{array}\right], B=\left[\begin{array}{ll}1 & 2 \\ 2 & 1 \\ 0 & 1\end{array}\right]\), then \((A B)^{-1}\) is

78788 If \(A=\left[\begin{array}{ll}1 & 1 \\ 1 & 2\end{array}\right], B=\left[\begin{array}{ll}4 & 1 \\ 3 & 1\end{array}\right]\), then \((A+B)^{-1}=\)

78789 If \(\mathrm{AX}=\mathrm{B}\), where \(\mathrm{A}=\left[\begin{array}{ccc}1 & -1 & 1 \\ 2 & -1 & 0 \\ 3 & 3 & -4\end{array}\right], \mathrm{B}=\left[\begin{array}{l}1 \\ 1 \\ 2\end{array}\right]\)
and \(X=\left[\begin{array}{l}x \\ y \\ z\end{array}\right]\), then \(x+y+z=\)

78790 If \(A=\left[\begin{array}{ccc}0 & -1 & 0 \\ -1 & 0 & 0\end{array}\right]\), then

78787 If \(A=\left[\begin{array}{lll}1 & 2 & 1 \\ 2 & 1 & 0\end{array}\right], B=\left[\begin{array}{ll}1 & 2 \\ 2 & 1 \\ 0 & 1\end{array}\right]\), then \((A B)^{-1}\) is

78788 If \(A=\left[\begin{array}{ll}1 & 1 \\ 1 & 2\end{array}\right], B=\left[\begin{array}{ll}4 & 1 \\ 3 & 1\end{array}\right]\), then \((A+B)^{-1}=\)

78789 If \(\mathrm{AX}=\mathrm{B}\), where \(\mathrm{A}=\left[\begin{array}{ccc}1 & -1 & 1 \\ 2 & -1 & 0 \\ 3 & 3 & -4\end{array}\right], \mathrm{B}=\left[\begin{array}{l}1 \\ 1 \\ 2\end{array}\right]\)
and \(X=\left[\begin{array}{l}x \\ y \\ z\end{array}\right]\), then \(x+y+z=\)

78790 If \(A=\left[\begin{array}{ccc}0 & -1 & 0 \\ -1 & 0 & 0\end{array}\right]\), then

78787 If \(A=\left[\begin{array}{lll}1 & 2 & 1 \\ 2 & 1 & 0\end{array}\right], B=\left[\begin{array}{ll}1 & 2 \\ 2 & 1 \\ 0 & 1\end{array}\right]\), then \((A B)^{-1}\) is

78788 If \(A=\left[\begin{array}{ll}1 & 1 \\ 1 & 2\end{array}\right], B=\left[\begin{array}{ll}4 & 1 \\ 3 & 1\end{array}\right]\), then \((A+B)^{-1}=\)

78789 If \(\mathrm{AX}=\mathrm{B}\), where \(\mathrm{A}=\left[\begin{array}{ccc}1 & -1 & 1 \\ 2 & -1 & 0 \\ 3 & 3 & -4\end{array}\right], \mathrm{B}=\left[\begin{array}{l}1 \\ 1 \\ 2\end{array}\right]\)
and \(X=\left[\begin{array}{l}x \\ y \\ z\end{array}\right]\), then \(x+y+z=\)

78790 If \(A=\left[\begin{array}{ccc}0 & -1 & 0 \\ -1 & 0 & 0\end{array}\right]\), then