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    Please help it would be much appreciated as i need to fathom this before i move on! Thanks guys and girls
    Solve simultaneous equations:

    3a+b=8
    3a^2+b^2=28
    Rearrange eq 1: b=3a

    Sub it into 2: 3a^2+(8-3a)^2=28
    You get -6a^2-48a+64=28
    -6a^2-48a+36=0

    I then divided it by -6 to get: a^2+8a-6=0
    Im stuck here where theres no numbers that x to get -6 and + to get 8. What should i do or have i made a mistake? Please explain! Thanks
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    I didn't get: -6a^2-48a+36=0.

    Try doing this step by step:

    3a+b=8
    therefore, b=8-3a
    3a^2+b^2-28=0
    Sub in.

    Then you get 3a^2+(8-3a)^2-28=0
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    (Original post by YsfAli)
    Please help it would be much appreciated as i need to fathom this before i move on! Thanks guys and girls
    Solve simultaneous equations:

    3a+b=8
    3a^2+b^2=28
    Rearrange eq 1: b=3a

    Sub it into 2: 3a^2+(8-3a)^2=28
    You get -6a^2-48a+64=28
    -6a^2-48a+36=0

    I then divided it by -6 to get: a^2+8a-6=0
    Im stuck here where theres no numbers that x to get -6 and + to get 8. What should i do or have i made a mistake? Please explain! Thanks
    Hi,
    Hint: you made the mistake when you squared -3a. Re-check that bit.
    Hope this helps!
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    (Original post by Reety)
    I didn't get: -6a^2-48a+36=0.

    Try doing this step by step:

    3a+b=8
    therefore, b=8-3a
    3a^2+b^2-28=0
    Sub in.

    Then you get 3a^2+(8-3a)^2-28=0
    Expand.
    Thanks bro, did just realise my silly mistake. Thanks anyway!
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    (Original post by Angel28)
    Hi,
    Hint: you made the mistake when you squared -3a. Re-check that bit.
    Hope this helps!
    Yeah i did a silly mistake should have spotted that. Thanks for the help!
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    (Original post by YsfAli)
    Thanks bro, did just realise my silly mistake. Thanks anyway!
    No worries, did you get your answer in the end?
    Spoiler:
    Show
    Answer: (a-1)(a-3)=0
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    (Original post by YsfAli)
    Yeah i did a silly mistake should have spotted that. Thanks for the help!
    No problem
 
 
 
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