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    x-1 (all over 3) – 3x +1 (all over 5) = 1 (sorry the numbers 3/5 are fractions)


    Can anybody help me to solve this, i know you cross multiply, but i'm not sure what you do with the = 1 part?? :confused: and to think i am doing higher GCSE maths ahem...also how would you factorise:
    6a + 10ab - 8a squared b????

    Thannnnnksssssssss again... :rolleyes:
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    (Original post by gemma.....)
    x-1 – 3x +1 = 1 (sorry the numbers 3/5 are denominators over fractions)
    3 5

    Can anybody help me to solve this, i know you cross multiply, but i'm not sure what you do with the = 1 part?? :confused: and to think i am doing higher GCSE maths ahem...also how would you factorise:
    6a + 10ab - 8a squared b????

    Thannnnnksssssssss again... :rolleyes:
    Are you meaning this then: (x-1)/3-3x/5+1=1?
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    (Original post by meepmeep)
    Are you meaning this then: (x-1)/3-3x/5+1=1?
    sorry, i mean it so x-1 is a numerator and in a fraction over 3 and the other part is over 5
    like a 1/3, one over 3 ....LOL
    do you understand??? i'll try and do it in word or something
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    (Original post by gemma.....)
    sorry, i mean it so x-1 is a numerator and in a fraction over 3 and the other part is over 5
    like a 1/3, one over 3 ....LOL
    do you understand??? i'll try and do it in word or something
    I get you now.
    (x-1)/3-(2x+1)/5=1
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    (Original post by gemma.....)
    sorry, i mean it so x-1 is a numerator and in a fraction over 3 and the other part is over 5
    like a 1/3, one over 3 ....LOL
    do you understand??? i'll try and do it in word or something
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    You want to add the two together by making the two denominators the same, so multiply the first by 5 and the second by 3, giving:

    5(x-1)/15-3(2x+1)/15=1
    (5x-5-6x-3)/15=1
    -x-8=15
    -x=23
    x=-23

    (which if you substitute back in then works)
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    oh ok seems weird..but thank you..i am having a bit of a bad day with maths LOL, i never did like the subject.
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    hmm i think meep made a mistake readign the questions is it not:
    5(x-1)/15-3(3x+1)/15=1
    instead of
    5(x-1)/15-3(2x+1)/15=1
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    (Original post by andy_)
    hmm i think meep made a mistake readign the questions is it not:
    5(x-1)/15-3(3x+1)/15=1
    instead of
    5(x-1)/15-3(2x+1)/15=1
    I did realise that myself, but i know that it doesn't make much difference. As long as i can see the method i will be able to substitute in. I'm sure my teacher said you cross multiply though :confused: the answer seems weird! LOL
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    (Original post by andy_)
    hmm i think meep made a mistake readign the questions is it not:
    5(x-1)/15-3(3x+1)/15=1
    instead of
    5(x-1)/15-3(2x+1)/15=1
    Yep, you're right. Should be what you said. By the way, this method is cross-multiplying, as you're multiplying the top of one by the bottom of another and visa-versa to make the denominators equal. (and following through you should get x=-23/4 when you do it again)
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    (Original post by meepmeep)
    Yep, you're right. Should be what you said. By the way, this method is cross-multiplying, as you're multiplying the top of one by the bottom of another and visa-versa to make the denominators equal.
    OH YESSSSS !!!!!!!! :rolleyes: BIMBO ALERT!
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    (Original post by gemma.....)
    OH YESSSSS !!!!!!!! :rolleyes: BIMBO ALERT!
    Who, you? :confused: :eek:
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    (Original post by mik1a)
    Who, you? :confused: :eek:
    Yes, me why? Did you think i meant them??
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    (Original post by gemma.....)
    also how would you factorise:
    6a + 10ab - 8a squared b????
    I fink:

    2a(3+5b-4ab)
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    (Original post by andy_)
    I fink:

    2a(3+5b-4ab)
    oh yes, i get confused when to use the three term ones in brackets..thats why i struggled to do that. I am usuallygood at maths, but this past paper seems to have hard examples of questions in everything. for example i know how to change recurring decimals into fractions when say it is 0.2424 etc but when it is 0.024 what do i do?

    Thanks for the above.
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    (Original post by gemma.....)
    oh yes, i get confused when to use the three term ones in brackets..thats why i struggled to do that. I am usuallygood at maths, but this past paper seems to have hard examples of questions in everything. for example i know how to change recurring decimals into fractions when say it is 0.2424 etc but when it is 0.024 what do i do?

    Thanks for the above.
    You can have the long or the short answer. The short answer is just stick a zero after the 9s for every zero in between the decimal point and the first non-zero digit (in this case 1) at the end.

    So 0.2424....=24/99
    0.02424....=24/990
    0.002424...=24/9900
    0.000002424....=24/9900000

    and so on. I can give you the long answer, but is it only worth one mark on the paper? If so, you just need that really and don't need to know how it works.
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    (Original post by gemma.....)
    oh yes, i get confused when to use the three term ones in brackets..thats why i struggled to do that. I am usuallygood at maths, but this past paper seems to have hard examples of questions in everything. for example i know how to change recurring decimals into fractions when say it is 0.2424 etc but when it is 0.024 what do i do?

    Thanks for the above.
    Yeh I know what ya mean, i've been doing loads of past papers. Its always easy wen u know how.
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    (Original post by meepmeep)
    You can have the long or the short answer. The short answer is just stick a zero after the 9s for every zero in between the decimal point and the first non-zero digit (in this case 1) at the end.

    So 0.2424....=24/99
    0.02424....=24/990
    0.002424...=24/9900
    0.000002424....=24/9900000

    and so on. I can give you the long answer, but is it only worth one mark on the paper? If so, you just need that really and don't need to know how it works.
    it is worth 3 marks, but i see where you are coming from...ah would you do this for 3 marks:
    0.02424... x 10 = 0.24242424...
    0.0242424 x 1000 = 24.242424
    1000-990 = 24/990?? Kind of thing LOL
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    (Original post by gemma.....)
    it is worth 3 marks, but i see where you are coming from...ah would you do this for 3 marks:
    0.02424... x 10 = 0.24242424...
    0.0242424 x 1000 = 24.242424
    1000-990 = 24/990?? Kind of thing LOL
    The short answer: yes.
 
 
 
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