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I'm having trouble finding the answer for this, or really any Nth root problem. Here is the particular problem that I cannot figure out. A simple explanation of how to solve this would go a long way, thank you.

Evaluate the function $\sqrt[5]{-243}$.

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You are looking for the number $a$ with the property that $a^5 = -243$. Can you think of a number whose fifth power is $243$? –  Arturo Magidin Mar 26 '12 at 3:43
    
Oh my god that's it? Thank you! Edit: 3 –  stytown Mar 26 '12 at 3:45
    
Except $3$ doesn't work, because $3^5 = 243$ and you want the answer to be $-243$; so you'll need to do something to that $3$ to make sure you get $-243$ instead... –  Arturo Magidin Mar 26 '12 at 3:46
    
-3 =) Thank you Arturo –  stytown Mar 26 '12 at 3:51
    
For what it's worth, $\root5\of{-243}$ is not a function; it's a number. One key to success in Mathematics is understanding the vocabulary, and using it correctly. –  Gerry Myerson Mar 26 '12 at 5:24

1 Answer 1

You are looking for the number $a$ with the property that $a^5=−243$. Can you think of a number whose fifth power is 243? – Arturo Magidin Mar 26 at 3:43

Oh my god that's it? Thank you! Edit: 3 – stytown Mar 26 at 3:45

Except $3$ doesn't work, because $3^5=243$ and you want the answer to be $−243$; so you'll need to do something to that $3$ to make sure you get $−243$ instead... – Arturo Magidin Mar 26 at 3:46

-3 =) Thank you Arturo – stytown Mar 26 at 3:51

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Copy/pasting the relevant comments into a CW answer so that this question can be considered "answered" (when this answer is accepted or upvoted). Feel free to edit/improve. –  Isaac May 2 '12 at 6:59

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