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**Gazzer****Member**- Registered: 2013-03-23
- Posts: 5

Hi,

In the attached image the highlighted subtraction has me stumped. I just can't see how the answer could be (1-sqrt(7))x^2.

I would be very grateful if someone could explain how this is so.

Thanks.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,962

Hi;

I do not see any image.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **A number by itself is useful, but it is far more useful to know how accurate or certain that number is.**

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**Gazzer****Member**- Registered: 2013-03-23
- Posts: 5

Ha! I can't get that to work either!

As part of a polynomial long divisio is a subtraction -6x^2 - sqrt(7)(1-sqrt(7)x^2) the answer is (1-sqrt(7))x^2

I don't understand!

*Last edited by Gazzer (2013-03-23 22:34:52)*

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,962

Hi;

- -6x^2

What is that?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **A number by itself is useful, but it is far more useful to know how accurate or certain that number is.**

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**Gazzer****Member**- Registered: 2013-03-23
- Posts: 5

Sorry, I'm rushing. I have to take my wife to London in a minute! I've edited the original.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,962

Hi;

Is that the problem?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **A number by itself is useful, but it is far more useful to know how accurate or certain that number is.**

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**Gazzer****Member**- Registered: 2013-03-23
- Posts: 5

Yes. That's it.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,962

I am getting

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

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**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,000

So, I am guessing that you need to know why the remainder is 1-sqrt(7)x^2 in a certain polynomial long division?

*Last edited by anonimnystefy (2013-03-23 22:42:36)*

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

The knowledge of some things as a function of age is a delta function.

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**Gazzer****Member**- Registered: 2013-03-23
- Posts: 5

Bobbym :- I think I misled you. it should be -6x^2-(sqrt(7))(1-sqrt(7))x^2

anonimnystefy - yes.

Thanks for your help. I have to go now. I'll be back this evening.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,962

I am afraid then that their answer is correct!

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

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**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,000

I think we will need more details, so, see you then.

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

The knowledge of some things as a function of age is a delta function.

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