Fuente TeX:

 \left(\begin{array}{rr} 1 & 1 \\ 1 & 1 \end{array}\right),\quad \left(\begin{array}{rr} 1 & 0 \\ -1 & 2 \end{array}\right),\quad \left(\begin{array}{rr} 1 & 2 \\ 1 & -1 \end{array}\right) \text{y}\quad \left(\begin{array}{rr} 1 & 0 \\ 1 & 3 \end{array}\right)