If `A=[1 2 3 3-2 1 4 2 1]` , then show that `A^3-23 A-401=0` .

Explanation

To show that \( A^3 - 23A - 401I = 0 \) for the given matrix \( A \), we will follow these steps:

### Step 1: Define the Matrix A
The given matrix \( A \) is:
\[
A = \begin{bmatrix}
1 & 2 & 3 \\
3 & -2 & 1 \\
...