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# Help With Rationalising The Denominator Of Surds watch

1. Hi
I suck at surds!
Can anyone help with this question?
How do I rationalise this denominator?

5 divided by 3 square root 5

I've tried multiplying by root 5 over root 5 but the answer wouldn't fit in the answer space (on my maths)

thanks
2. multiply by 3 root 5 over 3 root 5
3. sorry its 5 divided by 3 plus square root 5
4. Multiply the top and the bottom by 3 - sqaureroot of 5.

5. Multiply top and bottom by 3 - squareroot of 5
6. thanks just worked it out myself but thanks anyway
7. why 3 - not + sorry?
8. You use the opposite sign. It comes from the difference of 2 squares.

9. of course! thank you so much

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Updated: October 2, 2010
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