Problem:
Find the characteristic polynomial of the following matrix:
$\left(
\begin{array}{cc}
 -6 & -9 \\
 6 & 3 \\
\end{array}
\right)$
Answer:
$x^2+3 x+36$
{'source': 'AMPS', 'file': 'amps/mathematica/linear_algebra/characteristic_polynomial/40724.txt'}