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Math Help - how do i start

  1. #1
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    how do i start

    I need to rationalize: 9 cuberoot of 2 over cuderooot of 5 - cuberoot of 2
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  2. #2
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    Recall that (a^3 -b^3)=(a-b)(a^2+ab+b^2).
    \frac{{\sqrt[3]{9}}}{{\sqrt[3]{5} - \sqrt[3]{2}}}\left( {\frac{{\sqrt[3]{{25}} + \sqrt[3]{{10}} + \sqrt[3]{4}}}{{\sqrt[3]{{25}} + \sqrt[3]{{10}} + \sqrt[3]{4}}}} \right)=?
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  3. #3
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    okay but in order for it to be simplified i can't have a radicand in the denominator so do i mulitply everything by the third power?
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  4. #4
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    Quote Originally Posted by kandela573 View Post
    okay but in order for it to be simplified i can't have a radicand in the denominator so do i mulitply everything by the third power?
    Follow through with the multiplication that Plato has indicated and see what happens.
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  5. #5
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    Quote Originally Posted by kandela573 View Post
    okay but in order for it to be simplified i can't have a radicand in the denominator so do i mulitply everything by the third power?
    Can you do this, \left( {\sqrt[3]{5} - \sqrt[3]{2}} \right)\left( {\sqrt[3]{{25}} + \sqrt[3]{{10}} + \sqrt[3]{4}} \right)=?

    If not, why were you asked to do this problem?
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