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    Ok, This one has me confused

    7.Take out a common factor first of all, and then factorise the quadratic factor:

    (a) X^3 - x


    (b) 2x^3 - 18x

    If Someone could help me out by showing some working out that would be great!
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    Take out common factor

    a) x(x^2-1)

    b)2x(x^2-9)

    Hope that helps.
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    Im assuming sketching graphs?

    Think of it this way

    x^3 - x common factor is x

    so x(x^2-1)
    Factorize x^-1 which is factorizing the quadratic factor

    Its all in the question

    Use the same method for (b)
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    (Original post by Shakaa)
    Ok, This one has me confused

    7.Take out a common factor first of all, and then factorise the quadratic factor:

    (a) X^3 - x


    (b) 2x^3 - 18x

    If Someone could help me out by showing some working out that would be great!
    I am not quite sure if you mean this but here it is:

    a) x is common in both so:
    x^3-x= x(x^2-1)

    b) 2x is the common factor therefore:
    2x^3-18x= 2x(x^2-9)

    Hope this is what you were looking for
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    take out the common factor, in this example x

    and then the next thing is to factorise it into a quadratic:

    i.e. (x + a) (x + b)

    in both the examples you have: b = -a

    hope that helps!
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    (Original post by Aninja)
    Take out common factor

    a) x(x^2-1)

    b)2x(x^2-9)

    Hope that helps.
    you haven't actually finished the second question there. Don't know if that was your intention or not..
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    (Original post by Nytram12)
    you haven't actually finished the second question there. Don't know if that was your intention or not..
    If I did that I would of given him the answer. He only asked for some working out. He can work out the rest, hopefully.
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    (Original post by Shakaa)
    Ok, This one has me confused

    7.Take out a common factor first of all, and then factorise the quadratic factor:

    (a) X^3 - x


    (b) 2x^3 - 18x

    If Someone could help me out by showing some working out that would be great!
    a) x^3 - x

    => x(x^2-1)
    => x(x+1)(x-1)

    b)2x^3 - 18x

    => x(2x^2 -18)
    => x(2x + 6)(x-3)
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    (Original post by Shakaa)
    Ok, This one has me confused

    7.Take out a common factor first of all, and then factorise the quadratic factor:

    (a) X^3 - x


    (b) 2x^3 - 18x

    If Someone could help me out by showing some working out that would be great!
    a) Take out the common factor 'x' and factorise. You are left with x^2 - 1 You can factorise this using the difference of two squares

    b) Again, take out the common factor 'x' and rewrite equation. You are left with a quadratic to factorise once more.
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    (Original post by gottastudy)
    a) Take out the common factor 'x' and factorise. You are left with x^2 - 1 You can factorise this using the difference of two squares

    b) Again, take out the common factor 'x' and rewrite equation. You are left with a quadratic to factorise once more.

    Thanks for the help got sorted in the end, I was using the AC method to factorise instead of the AB >.<
 
 
 
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