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Math Help - find one matrix X such that AX = B

  1. #1
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    find one matrix X such that AX = B

    if
    A = [1 -2 -1]
    A = [2 -3 1]
    A = [-3 5 0]

    and
    B = [0 1 0]
    B = [-1 3 2]
    B = [1 -4 -2]

    find one matrix X such that AX = B.

    A and B are 3x3 matrix above
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  2. #2
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    x=a^{-1} b.
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  3. #3
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    Quote Originally Posted by Krizalid View Post
    x=a^{-1}b.
    But A and B both end up with a row of zeros, they don't have an inverse.
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  4. #4
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    B doesn't need to be invertible, just A, and A is invertible.
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  5. #5
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    Invertible?

    Quote Originally Posted by Krizalid View Post
    B doesn't need to be invertible, just A, and A is invertible.
    How is A invertible? Won't one find a row of zeroes on the left-hand side of the augmented matrix, implying that A is singular? Incidentally, the same situation will arise with B.
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  6. #6
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    what's its determinant?
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  7. #7
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    Quote Originally Posted by Krizalid View Post
    what's its determinant?
    Such that it's not invertible.
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  8. #8
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    ohh, i just realized that i got a typo in the third row when computing the determinant.

    anyway, there's no X, but at least the OP knows now how to solve the problem.
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  9. #9
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    I have got the solution for the question,
    X = [-2 3 4]
    X = [-1 1 2]
    X = [0 0 0 ]

    thanks for the help
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