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Let α be a root of the equation x 2 + x + 1 = 0 and the matrix A = 3 1 ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎣ ⎡ α α α α 4 2 2 1 1 1 1 1 , then the matrix A 31 is equal to

1. I 3
2. A 3
3. A 2
4. A

Correct answer: A 3

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