Results 1 to 6 of 6

Math Help - Factoring polynomials.

  1. #1
    Newbie
    Joined
    Jan 2011
    Posts
    8

    Factoring polynomials.

    1) x=(x^3)-(3x^2)-13x+15

    Its zeros are ?,?,? (3 answers)


    2)The polynomial of degree 4, p(x) has a root of multiplicity 2 at x=2 and roots of multiplicity 1 at x=0 and x=-2. Its lead coefficient is 5.
    Find a formula for . p(x)
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
    Quote Originally Posted by wwinston View Post
    1) x=(x^3)-(3x^2)-13x+15

    Its zeros are ?,?,? (3 answers)
    \displaystyle x=x^3-3x^2-13x+15

    \displaystyle 0=x^3-3x^2-14x+15

    Use the factor theorem with factors of 15 to check for integer solutions.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,691
    Thanks
    449
    Quote Originally Posted by wwinston View Post
    1) x=(x^3)-(3x^2)-13x+15

    Its zeros are ?,?,? (3 answers)


    2)The polynomial of degree 4, p(x) has a root of multiplicity 2 at x=2 and roots of multiplicity 1 at x=0 and x=-2. Its lead coefficient is 5.
    Find a formula for . p(x)
    did you mean f(x) = x^3 - 3x^2 - 13x + 15 ? if so, note that f(1) = 0 ... you should now be able to find the other two zeros.


    look at the following polynomial in factored form ...

    p(x) = ax(x-b)(x-c)^2

    it has a leading coefficient a , root at x = 0 , root at x = b , and a root of multiplicity two at x = c
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    Joined
    Dec 2007
    From
    Ottawa, Canada
    Posts
    3,102
    Thanks
    68
    Quote Originally Posted by wwinston View Post
    1) x=(x^3)-(3x^2)-13x+15
    You must mean this: x^3 - 3x^2 - 13x + 15 = 0 ; right?
    You can tell easily that x=1 is a solution; so do a division by x-1 next.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Jan 2011
    Posts
    8
    yeah thats what I meant...

    i factored and got

    x(x-2) (x-1) = 0

    figuring the answers would be 0,2,1

    the only one that is right is 1..i can check the answers to see if im right unlimited times
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
      (x^3 - 3x^2 - 13x + 15)\div (x-1) = x^2-2x-15
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Factoring Polynomials Help
    Posted in the Algebra Forum
    Replies: 1
    Last Post: January 13th 2010, 04:47 PM
  2. factoring polynomials
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: September 20th 2009, 01:05 AM
  3. Replies: 2
    Last Post: August 22nd 2009, 10:57 AM
  4. Factoring Polynomials
    Posted in the Algebra Forum
    Replies: 5
    Last Post: January 10th 2009, 01:03 PM
  5. Replies: 5
    Last Post: November 29th 2005, 03:22 PM

Search Tags


/mathhelpforum @mathhelpforum