Question

Which expression gives the determinant of the matrix?
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Answer choices:
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Answer 1

do you remember the rule for reducing an nth order matrix to n n-1th order matrices? the signs on the cofactors alternate and you need to make sure your selection for the minor matrices are correct.

Answer 2

No, I'm not aware of the rule for 'reducing an nth order matrix to n n-1th order matrices. Could you please show me how?

Answer 3

it's really just something you need to remember

Answer 4

Ah, that's a complex process right there. o-o

Answer 5

there's a lot of theory behind it in linear algebra, but I don't know what level math you are required to do this for.

Answer 6

Oh okay.

Answer 7

it's just a pattern you need to commit to memory at this point

Answer 8

Not much I can do to help you. Here's the general form. You can look it up yourself if you want help remembering.

Answer 9

Thank you.

Answer 10

that's how most people remember it. Don't forget the minus sign on the \(a_{12}\)

Answer 11

Okay, thank you! Much appreciated. :)

Answer 12

no problem. a general remark, you can actually do this with any row or column of the matrix and the determinant will be the same. it can be useful if certain rows have "easier" coefficients than others. But for now you can probably just stick to the first row (as I have shown)

Answer 13

Ohh okay!