Spot my error in solving a linear system I almost always get the unit matrix if I try to get to an row reduced echelon form. I probably always make a mistake. Can you spot the error? What illegal operations could a beginner do while trying to solve a linear system?
\begin{array}{}
1 & 1 & 3 \\
-4 & -3 & -8 \\
-2 & -1 & -2 \\
1 & 2 & 7 \end{array}
2.
\begin{array}{}
1 & 1 & 3 \\
0 & 1 & 6 \\
0 & 1 & 4 \\
0 & -1 & -4  \end{array}
3.
\begin{array}{}
1 & 1 & 3 \\
0 & 1 & 6 \\
0 & 1 & 4 \\
0 & 0 & 0 \end{array}
4.
\begin{array}{}
1 & 1 & 3 \\
0 & 1 & 6 \\
0 & 0 & 2 \\
0 & 0 & 0 \end{array}
5.
\begin{array}{}
1 & 1 & 3 \\
0 & 1 & 6 \\
0 & 0 & 1 \\
0 & 0 & 0 \end{array}
6.
\begin{array}{}
1 & 1 & 3 \\
0 & 1 & 0 \\
0 & 0 & 1 \\
0 & 0 & 0 \end{array}
7.
\begin{array}{}
1 & 1 & 0 \\
0 & 1 & 0 \\
0 & 0 & 1 \\
0 & 0 & 0 \end{array}
8.
\begin{array}{}
1 & 0 & 0 \\
0 & 1 & 0 \\
0 & 0 & 1 \\
0 & 0 & 0 \end{array}

Your very first step on the very first row operation, unfortunately
