Answer:
System of equations:

Augmented matrix:
![\left[\begin{array}{cccc}1&2&2&6\\2&1&1&6\\1&1&3&6\end{array}\right]](https://img.qammunity.org/2020/formulas/mathematics/college/pspja9lcfku1oc14h3fp5rqzhxfmxbh2iu.png)
Reduced Row Echelon matrix:
![\left[\begin{array}{cccc}1&2&2&6\\0&1&1&2\\0&0&1&1\end{array}\right]](https://img.qammunity.org/2020/formulas/mathematics/college/zoq2hr6ovkzq284anp7o9c00dlesozhgze.png)
Explanation:
Convert the system into an augmented matrix:
![\left[\begin{array}{cccc}1&2&2&6\\2&1&1&6\\1&1&3&6\end{array}\right]](https://img.qammunity.org/2020/formulas/mathematics/college/pspja9lcfku1oc14h3fp5rqzhxfmxbh2iu.png)
For notation, R_n is the new nth row and r_n the unchanged one.
1. Operations:

Resulting matrix:
![\left[\begin{array}{cccc}1&2&2&6\\0&-3&-3&-6\\0&-1&1&0\end{array}\right]](https://img.qammunity.org/2020/formulas/mathematics/college/bse6q4gxc7nqkrsgwhlxrr2vfdemk88wnb.png)
2. Operations:

Resulting matrix:
![\left[\begin{array}{cccc}1&2&2&6\\0&1&1&2\\0&-1&1&0\end{array}\right]](https://img.qammunity.org/2020/formulas/mathematics/college/18ynfuqob261ewfokycyv4xg9bsugppycd.png)
3. Operations:

Resulting matrix:
![\left[\begin{array}{cccc}1&2&2&6\\0&1&1&2\\0&0&2&2\end{array}\right]](https://img.qammunity.org/2020/formulas/mathematics/college/rbo09ossy2zej9rb9myzz2nrxkpr8xuqxl.png)
4. Operations:

Resulting matrix:
![\left[\begin{array}{cccc}1&2&2&6\\0&1&1&2\\0&0&1&1\end{array}\right]](https://img.qammunity.org/2020/formulas/mathematics/college/zoq2hr6ovkzq284anp7o9c00dlesozhgze.png)