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    Everyone I've spoken to (including a maths teacher) says this Equation cannot be solved:

    Solve this equation to find a and b:

    x2 + 16x – 14 = (x+a)2 + b


    a=________ b=________




    it was in the OCR linear maths paper 2.


    Does anyone know how to do it because it is really bugging me...:confused:
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    a=8
    b=-30 (actually -78....Apologies)
    tbh

    Ever heard of completing the square. Good maths teacher you've got.

    This is all assuming those 2's are squareds.
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    (Original post by jpjs01)
    Everyone I've spoken to (including a maths teacher) says this Equation cannot be solved:

    Solve this equation to find a and b:

    x2 + 16x – 14 = (x+a)2 + b


    a=________ b=________




    it was in the OCR linear maths paper 2.


    Does anyone know how to do it because it is really bugging me...:confused:
    Can you use subscript or whatever it's called to show the equation properly. Thanks.
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    its completing the square

    quite easy,

    (x+8)^2

    (x+8)(x+8)= x^2 +8x+8x+64

    x^2+16-78

    =(x+8)^2 -78
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    (Original post by mlbbrown)
    a=8
    b=-30
    tbh

    Ever heard of completing the square. Good maths teacher you've got.

    This is all assuming those 2's are squareds.
    x2 + 16x – 14 = (x+a)2 + b

    (x + 8) ^2 = (x + 8) (x + 8)

    = x2 + 16x + 64

    Therefore,

    64 - (-14) = -78

    Therefore,

    a= 8
    b= -78
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    (Original post by mlbbrown)
    a=8
    b=-30
    tbh

    Ever heard of completing the square. Good maths teacher you've got.

    This is all assuming those 2's are squareds.
    You sure about b? :confused:
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    Oh yes, it's actually been a long day - now as you mention it.
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    Yeah I think you should be having some words with your maths teacher to be honest.
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    Therefore,

    a= 8
    b= -78
    Reply With Quote
    This one.
    Isn't this a standard GCSE question?
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    (Original post by jpjs01)
    Everyone I've spoken to (including a maths teacher) says this Equation cannot be solved:

    Solve this equation to find a and b:

    x2 + 16x – 14 = (x+a)2 + b


    a=________ b=________




    it was in the OCR linear maths paper 2.


    Does anyone know how to do it because it is really bugging me...:confused:
    x^2 +16x-14

    (x+8)^2-64-14

    (x+8)^2-78 \rightarrow a=8 \, \, \, b=-78
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    (Original post by jpjs01)
    Everyone I've spoken to (including a maths teacher) says this Equation cannot be solved:

    Solve this equation to find a and b:

    x2 + 16x – 14 = (x+a)2 + b


    a=________ b=________




    it was in the OCR linear maths paper 2.


    Does anyone know how to do it because it is really bugging me...:confused:
    You don't even have to formally complete the square, you can do just do it by inspection:

    if you expand the bracket you get x^2 + 2ax + a^2, so you know that the coefficient on x has to be equal on both sides of the equation so 2a=16 ie a=8. If a=8 a^2 is 64 and you know that 64 + b = -14 ie b=-78.

    Your maths teachers must be terrible.
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    Hahaha I would swop schools if I was you, if your teacher can't solve that lol
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    (Original post by Ewan)
    Hahaha I would swop schools if I was you, if your teacher can't solve that lol

    bit late now eh?
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    (Original post by KwungSun)
    Your maths teachers must be terrible.
    I agree, seriously bad, it seems he cannot even do GCSE level maths let alone teach it.
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    you have bad teachers
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    Your Maths teacher isn't called Miss Martin is she?
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    (Original post by mlbbrown)
    a=8
    b=-30 (actually -78....Apologies)
    tbh

    Ever heard of completing the square. Good maths teacher you've got.

    This is all assuming those 2's are squareds.
    how did u get -30 before :confused:
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    lol you're predicted A* but no disrespect that was a relatively easy question.
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    im struggling to see how someone with probably a degree in maths cannot solve this?

    open out your brackets and then do it by coefficients.... 2a=16 and a^2 + b = -14
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    (Original post by georgeElsworth)
    im struggling to see how someone with probably a degree in maths cannot solve this?

    open out your brackets and then do it by coefficients.... 2a=18 and a^2 + b = -14
    It's a real shame that that's wrong...
 
 
 

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