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    Express f(x)=2x^3+5x^2+x-2 in fully factorised form.

    So this is my working: Name:  20151108_114937.jpg
Views: 58
Size:  327.0 KB

    But the answer should be f(x)=(x+1)(x+2)(2x-1). What did I do wrong?
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    (Original post by Airess3)
    Express f(x)=2x^3+5x^2+x-2 in fully factorised form.

    So this is my working: Name:  20151108_114937.jpg
Views: 58
Size:  327.0 KB

    But the answer should be f(x)=(x+1)(x+2)(2x-1). What did I do wrong?
    You're going to have to post the rest of your working. Can't make sense of that as it stands.
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    (Original post by ghostwalker)
    You're going to have to post the rest of your working. Can't make sense of that as it stands.
    That's all my working, I put the numbers into the synthetic division from the equation f(x)=2x^3+5x^2+x-2
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    (Original post by Airess3)
    That's all my working, I put the numbers into the synthetic division from the equation f(x)=2x^3+5x^2+x-2
    OK, so where do you get the top line of "2 5 -4" from? I can't see how it relates to your polynomial.
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    (Original post by Airess3)
    Express f(x)=2x^3+5x^2+x-2 in fully factorised form.

    So this is my working: Name:  20151108_114937.jpg
Views: 58
Size:  327.0 KB

    But the answer should be f(x)=(x+1)(x+2)(2x-1). What did I do wrong?
    Are you given any factors to begin with?

    My approach would be to try some small numbers like +1 and -1 and see if f(1) = 0 or f(-1) = 0. Having done this you can then divide by the appropriate linear factor and reduce the problem to factorizing a quadratic.
 
 
 
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