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Math Help - negative exponents

  1. #1
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    negative exponents

    Need some help again.

    -2^-3 = ?

    The answer in the book is -9/8

    I thought it would be -1/8.

    Help please!
    Jerry
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  2. #2
    Senior Member topher0805's Avatar
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    -2^{-3}

    = -\frac {1}{2^3}

    = -\frac {1}{8}


    The book is wrong.
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  3. #3
    MHF Contributor Mathstud28's Avatar
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    Here you go

    Quote Originally Posted by Jerry Cunningham View Post
    Need some help again.

    -2^-3 = ?

    The answer in the book is -9/8

    I thought it would be -1/8.

    Help please!
    Jerry
    a^{-b}=\frac{1}{a^{b}}...therefore in this case since it is -2^{-3}=\frac{1}{-2^3}=\frac{1}{-8}=\frac{-1}{8}
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