If A=2-11-12-11-12, verify that A3-6A2+9A=4I=0 and hence find A-1

If $A = [\begin{matrix} 2 & - 1 & 1 \\ - 1 & 2 & - 1 \\ 1 & - 1 & 2 \end{matrix}]$ , verify that $A^{3} - 6 A^{2} + 9 A = 4 I = 0$ and hence find $A^{- 1}$

Matching exercise

Match the items on the right to the items on the left.

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