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Math Help - How is this radical being reduced?

  1. #1
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    How is this radical being reduced?

    Hi all,

    I'm going through a application for learning maths and I've hit a confusing point, unfortunately it fails to depart with any information on workings out of a problem.

    The app informs me that:

    x = \frac{4 \pm \sqrt{20}}{2}}

    Reduces to this:

    x = {2 \pm \sqrt{5}}

    I have no idea how that radical is being divide by the whole number, basically I need to know how I would make this:

    \frac{\sqrt{20}}{2}}

    Reduce to this:

    \sqrt{5}

    Thanks in advance.
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  2. #2
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    \displaystyle \frac{\sqrt{20}}{2}} = \frac{\sqrt{4\times 5}}{2}}=\frac{\sqrt{4}\sqrt{ 5}}{2}} = \frac{2\sqrt{ 5}}{2}} = \sqrt{ 5}
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  3. #3
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    That's Fantastic! Thanks
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  4. #4
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    Quote Originally Posted by code View Post
    That's Fantastic! Thanks
    No, that's pickslides !
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  5. #5
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    Fantastic is off solving much more advanced problems.
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  6. #6
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    Quote Originally Posted by DrSteve View Post
    Fantastic is off solving much more advanced problems.
    Maybe it's relative?
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  7. #7
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    Don't forget the alternative...(as it could be dangerous to have "picks" agree with you)

    \displaystyle\frac{\sqrt{20}}{2}=\frac{\sqrt{20}}{  \sqrt{4}}=\sqrt{\frac{20}{4}}
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  8. #8
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    FANTASTIC Archibald!
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