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Math Help - dont bother reading, cant delete thread

  1. #1
    Junior Member
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    dont bother reading, cant delete thread

    Now I kind of have an idea of what im doing(by this, I mean I can take an educated guess as to what the answer is and be correct sometimes), but im looking for an explanation more than anything

    I have this problem: (x + 1)^2 = -9

    I then put a radical sign over the -9, get rid of the exponent and end up with

    x + 1 = (assume a radical sign) -9

    the -9 turns into 3i, because the SR of 9 is 3, and the negative factors out and makes an imaginary number

    so far so good, until I see the answer is -1 plus or minus 3i

    Unfortunately my book isnt very good, I was wondering if someone can help me finish the problem from where I left off.
    Last edited by CaptainBlack; December 9th 2010 at 11:18 PM. Reason: deleted post restored
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  2. #2
    MHF Contributor
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    \displaystyle x=-1\pm 3i

    A square root has two answers and you need to subtract the one to solve for x.
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  3. #3
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    Quote Originally Posted by dwsmith View Post
    \displaystyle x=-1\pm 3i

    A square root has two answers and you need to subtract the one to solve for x.
    it came to me fairly quickly after posting it for some reason. Thank you anyway!
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  4. #4
    Super Member Bacterius's Avatar
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    What kind of person deletes his solved threads so that other people can't read them ? Do not delete your solved threads, it's in the rules. Thanks.
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