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    solve the equation x^3-5x^2-2x+24=0

    help
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    -2 is a root

    trial and error is worth a go if you're doing exam questions
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    (Original post by gorila7)
    solve the equation x^3-5x^2-2x+24=0

    help
    try the factor theorem. Essentially trial and error until you get your first factor. After that, give algebraic long division a go to get the other factors. Or just keep doing the factor theorem.
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    If this is the only thing you're given then it would seem that factor theorem is the only way to go. Once you find one root, you can use division to find the remaining.
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    use the factor theorem
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    (Original post by Woffles)
    If this is the only thing you're given then it would seem that factor theorem is the only way to go. Once you find one root, you can use division to find the remaining.
    Can you show me how to do this
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    (Original post by TobeTheHero)
    use the factor theorem
    can you show me how to do this
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    (Original post by problemsolver)
    -2 is a root

    trial and error is worth a go if you're doing exam questions
    can you show me how to do this
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    First you put some numbers in to see which one(s) will give 0

    Can you see why -2 was given by the posters above
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    If x=2 is a solution, then f(-2) = o since x-2=0 which makes the rest of the polynomial equal zero. Then write it as a quadratic of form ax^2+bx+c multiplied by a bracket and find the co-efficients of the quadratic. Then solve; you have your equation solved.
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    (Original post by gorila7)
    solve the equation x^3-5x^2-2x+24=0

    help
    The factor theorem

    If

    f(x) = x^3 - 5x^2 -2x+24

    then to solve f(x)=0, you use trial and error first

    If

    f(a)=0

    then

    (x-a)

    is a factor.

    Use algebraic long division to solve the equation completely after you've found 1 factor.
 
 
 
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