Results 1 to 2 of 2

Math Help - factor theorem

  1. #1
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261

    factor theorem

    Factorise P(x)=x^3-7x-6

    I know that the constant term for this equation is -6 . Then , if (x-a) were to be a factor of P(x) , then a must be a factor of -6 .

    Why is it so ? My book doesn't further explain .
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Dec 2008
    From
    Scotland
    Posts
    901
    Quote Originally Posted by mathaddict View Post
    Factorise P(x)=x^3-7x-6

    I know that the constant term for this equation is -6 . Then , if (x-a) were to be a factor of P(x) , then a must be a factor of -6 .

    Why is it so ? My book doesn't further explain .
    Because when you put it in the form:

     P(x) = (x-a)(x^2+bx+c)

    Then a and c must multiply to give -6, and hence both must be factors.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Need help on factor theorem.
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: February 10th 2010, 01:35 AM
  2. factor theorem
    Posted in the Algebra Forum
    Replies: 8
    Last Post: January 5th 2009, 06:43 PM
  3. Factor theorem!
    Posted in the Algebra Forum
    Replies: 4
    Last Post: February 16th 2008, 04:16 AM
  4. Factor Theorem and Remainder Theorem
    Posted in the Algebra Forum
    Replies: 2
    Last Post: September 8th 2007, 10:50 AM
  5. factor theorem
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: March 7th 2007, 09:51 PM

Search Tags


/mathhelpforum @mathhelpforum