Problem:
Compute the trace of
$\left(
\begin{array}{ccccccc}
 3 & 2 & 5 & -7 & 0 & 8 & 1 \\
 -9 & 1 & 1 & 3 & -2 & 1 & -3 \\
 -7 & -8 & -2 & -6 & -1 & -10 & 8 \\
 5 & 3 & 7 & -6 & 9 & -8 & -9 \\
 4 & 5 & -3 & -10 & -6 & -6 & -1 \\
 9 & 9 & -9 & 7 & 4 & 2 & -9 \\
 3 & -9 & 8 & -2 & 2 & 4 & -6 \\
\end{array}
\right)$.
Answer:
$-14$
{'source': 'AMPS', 'file': 'amps/mathematica/linear_algebra/trace/36041.txt'}