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if A and B are 3 x 3 matrices, det(A) = -1, det(B) = -2, then what is det(-2A) ? If possible please include workings, thanks!?

2 Answers

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  • Anonymous
    3 years ago
    Favorite Answer

    det(B) isn't used so why say it is -2 ????

    For an n x n matrix, A: det(cA) = cⁿdet(A)

    This is a standard relationship you should be given (formula sheet?).

    det(-2A) = (-2)³det(A) (since A is 3x3)

    . . . . . . . = -8 x -1

    . . . . . . . = 8

  • cidyah
    Lv 7
    3 years ago

    det(-2A) = (-2)^3 det(A) = -8(-1) = 8

    https://gyazo.com/5348a19c38126cf76230a0af52bfdc6c

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