נמצא פ"א: p_A(x)=|xI-A|=\begin{vmatrix} x-5 & 0 & 0 &0 \\ -1& x-4 & 0 & 0\\
-2& -3&x- 3 &0 \\
-4 & -5 &-6 &x- 3 \end{vmatrix}=(x-5)(x-4)(x-3)^2