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\overline{A}=\left( \left.\begin{matrix} 1 & 2 & 1 \ \\ -4 & 0 & -6 \ \\ 0 & 0 & 1 \ \end{matrix} \right | \begin{matrix} \ 0\ \\ \ 2\ \\ -1 \ \end{matrix}\right ) \Longrightarrow \left.\begin{align} x+2y+z=0 & \\ -4x-6z =2 & \\ z=-1 \end{align} \right\}