Results 1 to 2 of 2

Thread: Need help with this one

  1. #1
    Newbie
    Joined
    Oct 2009
    From
    MS
    Posts
    13

    Need help with this one

    Find all zeros of the function and write the polynomial as a product of linear factors.

    F(x)=x^3+2x^2-3X-10
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    May 2009
    From
    New Delhi
    Posts
    153
    you see,if we put x= 2 then f(x)=0
    therefore (x-2) is a factor of f(x)

    now divide $\displaystyle x^3+2x^2-3X-10 $ by (x-2) to get other factors
    if stuck check spoiler
    Spoiler:

    $\displaystyle x^3+2x^2-3X-10 = (x-2)(x^2+4x+5) $
    solving $\displaystyle (x^2+4x+5)$ using $\displaystyle \frac {-b \pm \sqrt{b^2-4ac}}{2a}$
    we get x = $\displaystyle (-2\pm i) $
    $\displaystyle \therefore x^3+2x^2-3X-10 = (x-2)(x+2+i)(x+2-i) $
    Follow Math Help Forum on Facebook and Google+


/mathhelpforum @mathhelpforum