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# Surds help

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Why bother with a post grad course - waste of time? 17-10-2016
1. Hi

Can anyone help with the following:

(2+√2)(3+√5)(√5-2)
(√5-1)(1+√2)

I have managed to get to the following but not sure what to do from here:

2√5 – 2 + √10 + √50 - 6√2
√5 + √10 - 1 - √2

Thanks
2. (Original post by Flutegirl02)
Hi

Can anyone help with the following:

(2+√2)(3+√5)(√5-2)
(√5-1)(1+√2)

I have managed to get to the following but not sure what to do from here:

2√5 – 2 + √10 + √50 - 6√2
√5 + √10 - 1 - √2

Thanks
What is your objective? If it's to rationalise the denominator then just multiply your fraction by before you expand the brackets.
3. Thanks. Yeah it's rationalising. I'll have a go tomorrow.
4. The trick is to keep the denominator factorised, at least until you have done the 'multiply top and bottom by this' trick.

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