Equation point from a matrix

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Lord Dark
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Homework Statement


Good evening everyone,, I have the following problem:
Text problem: Let A be the matrix [3 1; 2 1]. Find P(A) if P(x) = λx² − x + 1 where λ is the first digit of your student ID.



The Attempt at a Solution



disregarding the digit ,, he's giving me P(x) and want P(A) but A is a matrix ,, should I get the determinant of A then apply it in the equation ?? or it has some idea I need to know ??
 
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  • Text problem: Let A be the matrix [3 1; 2 1]. Find P(A) if P(x) = λx² − x + 1, where λ is the first digit of your student ID.
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You know how to multiply matrices

You know how to add matrices

I dare say maybe you can just plug in A directly and get an answer. This is pretty common, giving a polynomial where you think the input is supposed to be a number, but then you plug in matrices instead to see what you get
 
aha, got it ... Really it's very easy ,, I feel stupid :shy:

Thanks very much guys