Answer
See answers below
Work Step by Step
The coefficient matrix is: $A=\begin{bmatrix}
1 & 2 & -3\\
2 & 4 & -5\\
7 &2 &-1
\end{bmatrix}$
The right-hand side vector is: $b=\begin{bmatrix}
1 \\
2 \\
3
\end{bmatrix}$
The augmented matrix: $A^{\#}=\begin{bmatrix}
1 & 2 & -3|1\\
2 & 4 & -5|2\\
7&2&-1 |3\\
\end{bmatrix}$
