Answer
$\begin{bmatrix} 7 &-2 \\ 3 &-1\end{bmatrix}$
Work Step by Step
We need to augment the matrix by adding the Identity Matrix $\begin{bmatrix} 1 & 0 \\ 0 & 1\end{bmatrix}$
Therefore,
$\begin{bmatrix} 1& 2& 1 & 0 \\ 3& 7& 0 & 1\end{bmatrix}$
Now, multiply row $1$ by $-3$ and add it to row $2$
We have : $\begin{bmatrix} 1 & 0 & 7 &-2 \\ 0 & 1 &3 &-1\end{bmatrix}$
Our answer is: $\begin{bmatrix} 7 &-2 \\ 3 &-1\end{bmatrix}$
