Answer
\[
M=
\left[ {\begin{array}{cc}
9 & -4 \\
-2 & 1 \\
\end{array} } \right]
\]
Work Step by Step
We use the the formula
\[
M= \frac{1}{ad-bc}
\left[ {\begin{array}{cc}
d & -b \\
-c & a \\
\end{array} } \right]
\]
\[
M= \frac{1}{1}
\left[ {\begin{array}{cc}
9 & -4 \\
-2 & 1 \\
\end{array} } \right]
\]
