How many of the following matrices have an eigenvalue 1? $\left[\begin{array}{cc}1 & 0 \\ 0 & 0 \end{array} \right]\left[\begin{array}{cc}0 & 1 \\ 0 & 0 \end{array} \right] \left[\begin{array}{cc}1 & -1 \\ 1 & 1 \end{array} \right]$ and $\left[\begin{array}{cc}-1 & 0 \\ 1 & -1 \end{array} \right]$

x : eigen value x² - trace (A) + det (A) = 0, $\lambda$= 1 $\left[\begin{array}{cc}1 & 0 \\ 0 & 0 \end{array} \right]$: 1-2 + 1 = 0 $\left[\begin{array}{cc}0 & 1 \\ 0 & 0 \end{array} \right]: 1-0 + 0 \ne 0 $ $ \left[\begin{array}{cc}1 & -1 \\ 1 & 1 \end{array} \right]: 1-2 + 2 \ne 0$ $\left[\begin{array}{cc}-1 & 0 \\ 1 & -1 \end{array} \right]: 1+2 + 1\ne 0 $