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    1√ 28-2√ 63+√ 7
    i got -4√ 7 however the text book says the answer is -3√ 7. I was wondering whether i should have added 1 to the answer from 1√ 28 as I did not do it, but it does not make sense as 1√ 28=√ 28. Or does √ 7 mean you have to add 1 to the answer?
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    (Original post by p29)
    1√ 28-2√ 63+√ 7
    i got -4√ 7 however the text book says the answer is -3√ 7. I was wondering whether i should have added 1 to the answer from 1√ 28 as I did not do it, but it does not make sense as 1√ 28=√ 28. Or does √ 7 mean you have to add 1 to the answer?
    The first thing you should do is convert them all to their simplest form

    √28 = 2√7
    2√63 = 2(3√7) = 6√7

    So your equation is 2√7 - 6√7 + √7 = -3√7
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    All of the numbers under the root are multiples of 7, so break it down to  \sqrt{4\times 7} - 2 \sqrt{9 \times 7} + \sqrt{7}
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    I don't know if it's just me that doesn't quite get what you're saying, but maybe this'll help.

    √28 = √7√4 = 2√7

    So

    1√ 28-2√ 63+√ 7 = 2√7 - 6√7 + √7
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    I wrote 1√ 28=4√7 instead of 2√ 7 lol
 
 
 
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