EW:
\(\left(k - λ \right)^{2} \; \left(k - λ + 1 \right)^{2} = 0\)
k=-2
EW={-2,-1}
\(\small \left(\begin{array}{rrrr}\lambda=&-2&\left(\begin{array}{rrrr}0&2&0&-3\\0&1&0&0\\0&-1&0&4\\0&0&0&1\\\end{array}\right)&\left(\begin{array}{r}x1\\x2\\x3\\x4\\\end{array}\right) = 0\\\lambda=&-1&\left(\begin{array}{rrrr}-1&2&0&-3\\0&0&0&0\\0&-1&-1&4\\0&0&0&0\\\end{array}\right)&\left(\begin{array}{r}x1\\x2\\x3\\x4\\\end{array}\right) = 0\\\end{array}\right)\)
DimER ={2,2}
==> diag