Answer
\[
M=
\left[ {\begin{array}{cc}
1 & -3 & 2 & - 1 \\
0 & 1 & 1 & -1 \\
0&0&-3&3\\
\end{array} } \right]
\]
Work Step by Step
\[
M=
\left[ {\begin{array}{cc}
1 & -3 & 2 & - 1 \\
0 & 1 & 1 & -1 \\
0&2&-1&1\\
\end{array} } \right]
\]
\[
M=
\left[ {\begin{array}{cc}
1 & -3 & 2 & - 1 \\
0 & 1 & 1 & -1 \\
0-0&2-2&-1-2&1+2\\
\end{array} } \right]
\]
\[
M=
\left[ {\begin{array}{cc}
1 & -3 & 2 & - 1 \\
0 & 1 & 1 & -1 \\
0&0&-3&3\\
\end{array} } \right]
\]