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Changing the subject of a formula

  1. May 1, 2009 #1
    Ok, this most likely will be a silly question but im having trouble trying to make X the subject of the formula XA +BA = B

    im hoping someone is able to enlighten me

  2. jcsd
  3. May 2, 2009 #2

    matt grime

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    Homework Helper

    What are X, A and B? It matters as it tells you what rules of manipulation are valid.

    You can certainly subtract BA from both sides:

    XA = B-BA

    Now you need to 'divide' by A. If this is about real numbers, X=(B-BA)/A.

    (If it were matrices then assuming A is invertible, X=(B-BA)A^-1.)
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