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Math Help - (-5^2)^3 = -15625? What?

  1. #1
    Newbie alucheni's Avatar
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    (-5^2)^3 = -15625? What?

    Just like the subject header says:

    (-5^2)^3 = -15625?

    My calculator and text seem to agree. Why? Wouldn't the -5^2 in parenthesis process before the ^3? Shouldn't all exponent values outside the parenthesis create a positive number since -5^2 = 25?

    PEMDAS says parenthesis then exponents. I'm sure I'm missing something easy here...

    Thanks for any help.
    Oh and, hi everyone this is my first ever post.
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  2. #2
    Member pflo's Avatar
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    But the -5 is not being squared. This is the difference between (-5)^2 and -(5^2). Which way should it be if there are no parentheses? Do the exponent before the negative!!

    Then, once you know what the -5^2 equals (it is -25 and not 25), you can cube it. The result is negative.
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  3. #3
    Newbie alucheni's Avatar
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    doh

    Doh! Thank you sir.



    So, in the expression (-5^2)^3, the exponent on the outside is what dictates sign seeing as -5^2 is always going to be -25. Gotcha.
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