Hi
I haven't understood how to do these types of questions, could someone give a step by step answer please? thanks
"Express (2- √3)² in the form b + c√3, where b and c are integers to be found"
Thanks so much![]()
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eliwats
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- 09-09-2016 17:17
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usycool1
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- 09-09-2016 17:18
(Original post by eliwats)
Hi
I haven't understood how to do these types of questions, could someone give a step by step answer please? thanks
"Express (2- √3)² in the form b + c√3, where b and c are integers to be found"
Thanks so much -
Crack Cupcake
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- 09-09-2016 17:21
Consider this:
(2- √3)² is the same as (2- √3)(2- √3)
From there, you just use FOIL to multiply out the brackets. And don't worry, you will end up with an answer in the form b + c√3 (unless you're using a calculator, in which case, you'd end up being kicked out of the C1 exam, anyway.)
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eliwats
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- 09-09-2016 17:35
(Original post by Crack Cupcake)
Consider this:
(2- √3)² is the same as (2- √3)(2- √3)
From there, you just use FOIL to multiply out the brackets. And don't worry, you will end up with an answer in the form b + c√3 (unless you're using a calculator, in which case, you'd end up being kicked out of the C1 exam, anyway.)
I have expanded the brackets, that wasn't a problem but now I have 7-4√3, yet the question is asking for an answer as b + c√3. How do I proceed? -
Crack Cupcake
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- 09-09-2016 17:38
(Original post by eliwats)
hi
I have expanded the brackets, that wasn't a problem but now I have 7-4√3, yet the question is asking for an answer as b + c√3. How do I proceed? -
eliwats
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- 09-09-2016 17:56
(Original post by Crack Cupcake)
That's the right answer, since b and c can be either positive or negative, unless the question specifically states otherwise, so in this case, c is -4.
Thanks so much!!!
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