Exercise 4

Get the reduced echelon form of each.

• (a)  $\begin{pmatrix}0&2&1\\ 2&-1&1\\ -2&-1&0\end{pmatrix}$     (b)  $\begin{pmatrix}1&3&1\\ 2&6&2\\ -1&0&0\end{pmatrix}$