Help needed - Simplifying Watch

RachaelBee
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#1
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#1
I have been set a question and I'm completely stuck. I have the answer but no idea about how to get there. I'm a distance learner and my tutor is on holiday until August and I have a massive bee in my bonnet at the moment so any help would be greatly appreciated.

Question: simplify
5-√75
-2

I've got as far as:
5-(5√3)
-2

But apparently the answer is:
5(1-√3)
-2

How do I get to the answer?! Is it even possible? It wouldn't be the first time ICS have made a mistake but this seems like it would be a big mistake that someone would have picked up on so I get the feeling I'm just being really dim. Can someone PLEASE enlighten me? :confused:
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kara1
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I know this is working back from the answer but.. Multiply out the bracket on the top of the fraction in the answer and see what you get
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Mr M
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(Original post by RachaelBee)
I have been set a question and I'm completely stuck. I have the answer but no idea about how to get there. I'm a distance learner and my tutor is on holiday until August and I have a massive bee in my bonnet at the moment so any help would be greatly appreciated.

Question: simplify
5-√75
-2

I've got as far as:
5-(5√3)
-2

But apparently the answer is:
5(1-√3)
-2

How do I get to the answer?! Is it even possible? It wouldn't be the first time ICS have made a mistake but this seems like it would be a big mistake that someone would have picked up on so I get the feeling I'm just being really dim. Can someone PLEASE enlighten me? :confused:
There's no mistake. The answers are equivalent.

You should know ab + ac = a(b+c)
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HexBugMaster
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No it's not a mistake, you can take out 5 as the common factor from 5-(5√3) and thus get 5(1-√3)
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SaySaam
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(Original post by RachaelBee)
I have been set a question and I'm completely stuck. I have the answer but no idea about how to get there. I'm a distance learner and my tutor is on holiday until August and I have a massive bee in my bonnet at the moment so any help would be greatly appreciated.

Question: simplify
5-√75
-2

I've got as far as:
5-(5√3)
-2

But apparently the answer is:
5(1-√3)
-2

How do I get to the answer?! Is it even possible? It wouldn't be the first time ICS have made a mistake but this seems like it would be a big mistake that someone would have picked up on so I get the feeling I'm just being really dim. Can someone PLEASE enlighten me? :confused:
Both 5 and 5√3 have a multiple of 5 in them. 5=5x1 and 5√3=5x√3

You can factorise 5- 5√3 by taking a multiple of 5 out. You're multiplying everything inside the bracket by what's outside the bracket, in this case the 5.

Does that make it a little clearer?

Posted from TSR Mobile
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RachaelBee
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Thanks but I still don't get where the - goes? I'm feeling so stupid at the moment but my course material doesn't explain it and I haven't studied math in the last 6 years.
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HexBugMaster
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(Original post by RachaelBee)
Thanks but I still don't get where the - goes? I'm feeling so stupid at the moment but my course material doesn't explain it and I haven't studied math in the last 6 years.
5-5x(sq. rt. 3) = 5(1-1x(sq. rt. 3)

And don't worry, maths gets extremely tricky if you don't practise it for a while. If I miss my maths practice for a day I forget concepts I haven't worked on for enough, let alone not doing it for 6 years
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Mr M
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(Original post by RachaelBee)
Thanks but I still don't get where the - goes? I'm feeling so stupid at the moment but my course material doesn't explain it and I haven't studied math in the last 6 years.
Do you understand the following?

5 - 5x = 5(1-x)

This is exactly the same with x=\sqrt 3

Factorising expressions like this is a grade D skill at GCSE so you may need to spend some time studying the algebra section of a GCSE revision guide.
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HexBugMaster
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How does it happen that no one posts for a period of time and then everybody posts at the same time
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iCiaran
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(Original post by HexBugMaster)
How does it happen that no one posts for a period of time and then everybody posts at the same time
One person finds it, post bumps it back up to the sidebar and loads more people find it
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HexBugMaster
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(Original post by iCiaran)
One person finds it, post bumps it back up to the sidebar and loads more people find it
You cracked the mystery:holmes:
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m4ths/maths247
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(Original post by RachaelBee)
Thanks but I still don't get where the - goes? I'm feeling so stupid at the moment but my course material doesn't explain it and I haven't studied math in the last 6 years.
Hi
I know it's not much help at this stage but hopefully it may help others in the future.
I can't help thinking £470 for the ICS distance learning course is a lot of money given (i) The materials aren't great (ii) The support is often slow and (iii) The exams are not paid for.

If you hop on amazon a secondhand Bostock and Chandler Core Maths book for less than a tenner and help here should provide a god background for pure maths.

Good luck
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RachaelBee
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I get it!! Halle-freaking-lujah! Thank you so much everyone.
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