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    Please help with an explanation if that's ok:

    If 17x - b = 4ax + 9x - 3a for all real values of x then,

    A) a = -2, b = 6
    B) a = -2, b = -6
    C) a = 2, b = 6
    D) a = 8, b = -24
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    (Original post by flyingpanda786)
    Please help with an explanation if that's ok:

    If 17x - b = 4ax + 9x - 3a for all real values of x then,

    A) a = -2, b = 6
    B) a = -2, b = -6
    C) a = 2, b = 6
    D) a = 8, b = -24
    There's an easy but long way to do this, which is to substitute each of the choices and see which works (I don't necessarily recommend that, however think about exam technique - if you're stuck on a multiple choice question like this in an exam, the easiest way to get the mark is to just work out which option works and move on).
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    (Original post by flyingpanda786)
    Please help with an explanation if that's ok:

    If 17x - b = 4ax + 9x - 3a for all real values of x then,

    A) a = -2, b = 6
    B) a = -2, b = -6
    C) a = 2, b = 6
    D) a = 8, b = -24
    Factorise:

    17x - b = x(4a + 9) - 3a

    Now try comparing coefficients of x.
 
 
 
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