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\begin{document}
\begin{center}
{\bf Criss-Cross Method Illustration}
\end{center}

\[
\begin{array}{r|c|l|}
  &  N  &\\
\hline
B  &  \bar{A}_N    &  \bar{b}    \\
\hline
   &  - \bar{c}_N    &  -y \bar{b}    \\
\hline
\end{array}
\]
\begin{enumerate}
\item
\[
\begin{array}{r|ccc|l|}
  &  3 & 5 & 6  &\\
\hline
4  &   -1 & -2 & 5    &  -1   \\
2  &   4 & \underline{\overline{|-2|}} & -1    &  -3   \\
1  &   2 & 0 & 3    &  2   \\
\hline
   &   -3 & 1 & -1    &     \\
\hline
\end{array}
\]
\item
\[
\begin{array}{r|ccc|l|}
  &  3 & 5 & 6  &\\
\hline
4  &   -1 & -2 & 5    &  -2   \\
2  &   4 & -2 & -1    &  3   \\
1  &   \underline{\overline{|8|}} & 0 & 3    &  0   \\
\hline
   &   -3 & 1 & -1    &     \\
\hline
\end{array}
\]
\item
\[
\begin{array}{r|ccc|l|}
  &  3 & 5 & 6  &\\
\hline
4  &   -1 & -2 & 5    &  -2   \\
2  &   4 & 2 & 1    &  -3   \\
1  &   2 & 0 & 3    &  2   \\
\hline
   &   -3 & 1 & -1    &     \\
\hline
\end{array}
~~~~\mbox{Infeasible}
\]
\item
\[
\begin{array}{r|ccc|l|}
  &  3 & 5 & 6  &\\
\hline
4  &   -1 & -2 & 5    &  -2   \\
2  &   0 & -2 & -1    &  3   \\
1  &   -2 & 0 & 3    &  2   \\
\hline
   &   -3 & 1 & -1    &     \\
\hline
\end{array}
~~~~\mbox{Dual-Infeasible}
\]
\item
\[
\begin{array}{r|ccc|l|}
  &  3 & 5 & 6  &\\
\hline
4  &   -1 & -2 & 5    &  1   \\
2  &   0 & -2 & -1    &  3   \\
1  &   -2 & 0 & 3    &  0   \\
\hline
   &   3 & 1 & 1    &     \\
\hline
\end{array}
~~~~\mbox{(P) optimal tableau}
\]
\end{enumerate}
NOTE: These 5 illustrations do NOT correspond to the same LP.
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\end{document}
