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Math Help - negative fractional exponents

  1. #1
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    negative fractional exponents

    hey guys i needed help on understanding how to do these questions?

    a) (49)^(-3/2)

    b) (27/8)^(-1/3)

    c) -(25)^(1/2)
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  2. #2
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    49^{-3/2} = \frac{1}{49^{3/2}}
    49^{3/2}=\sqrt[3]{49^2}=\sqrt[3]{49^2}=13.39052
    Finally:
    49^{-3/2} =\frac{1}{13.39052}=0.07467971

    You can solve the others the same way. I hope it has been helpful.
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  3. #3
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    a.) (49)^(-3/2) is the same as writing 1 / [(49)^(3/2)]
    The 3/2 part is the same as the cube root of 49^2.

    b.) (27/8)^(1/3) = (8/27)^(1/3)

    c.) The exponent part takes precendence over the negative, which counts as a multiplication by -1. Therefore - [25^(1/2)], which just means to take the square root of 25 and multiply by -1. Answer is -5.
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  4. #4
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    Smile

    thanks guy that helped me out alot !!!
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  5. #5
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    Quote Originally Posted by Californiaboy View Post
    a.) (49)^(-3/2) is the same as writing 1 / [(49)^(3/2)]
    The 3/2 part is the same as the cube root of 49^2.
    not quite. it's the square root of 49 cubed ...

    \frac{1}{49^{\frac{3}{2}}} = \frac{1}{7^3} =  \frac{1}{343}<br />
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