hard core 1 surds question

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ruby598
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#1
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#1
10+ 7root5 + 38/1+2root5
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Zacken
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#2
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#2
(Original post by ruby598)
10+ 7root5 + 38/1+2root5
I assume you want to simplify it... please state so in the question, also remove ambiguity by using brackets so it's 38/(1 + 2root5) not 38/1+2root5

In any case, you'll want to rationalise the \displaystyle \frac{38}{1+2\sqrt{5}} by multiplying the top and bottom of the fraction by 1 - 2\sqrt{5}.
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Kevin De Bruyne
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#3
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#3
(Original post by ruby598)
10+ 7root5 + 38/1+2root5
How should you approach it? What have you tried so far?
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ubisoft
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#4
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#4
Rationalise the denominator by multiplying by the conjugate. (You should have been taught this)
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BrasenoseAdm
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#5
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#5
(Original post by Zacken)
I assume you want to simplify it... please state so in the question, also remove ambiguity by using brackets so it's 38/(1 + 2root5) not 38/1+2root5

In any case, you'll want to rationalise the \displaystyle \frac{38}{1+2\sqrt{5}} by multiplying the top and bottom of the fraction by 1 - 2\sqrt{5}.

As we think ubisoft is staying, before rationalising the denominator we suggest you treat this as a fraction and get both numerators under a common denominator.

You will end up with 80 + ??SQRT5 divided by 1 + 2SQRT5

Then rationalising this as ubisoft suggests should be fairly easy. Good luck!
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ruby598
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#6
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#6
Thank you! Yes I did mean simplify thank you

Posted from TSR Mobile
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IDK Tuition
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#7
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#7
Normally surds can be simplified in the form a√b or a√b + c. This can be achieved by breaking down the bigger surds and/or rationalising the denominator of any fraction. This question involves the latter.

Hope this helps,

Tom (IDK-tuition.com: online maths, economics and ACT tuition/resources)
Surds video https://www.youtube.com/watch?v=ozdopnMI67U
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ruby598
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#8
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#8
Thank you!
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