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Find the total area of the shaded polygon.$\newline$Area of polygon $=$ $\square$ square units$\newline$\begin{tabular}{|l|l|l|l|}$\newline$\hline \multicolumn{$9$}{|c}{$\ldots$} \\$\newline$\hline $7$ & $8$ & $9$ & $\mathbb{x}$ \\$\newline$\hline $4$ & $5$ & $6$ & - \\$\newline$\hline $1$ & $2$ & $3$ & - \\$\newline$\hline $0$ & & $(-1$ & \\$\newline$\hline$\newline$\end{tabular}