Results 1 to 2 of 2

Math Help - What are a, b and c?

  1. #1
    Member
    Joined
    Dec 2008
    Posts
    105

    What are a, b and c?

    Hi,

    This has complex numbers in

    I have the equation z^3 + az^2 + bz + c = 0 where the solutions for z= -2-i, -2+i and 2.

    How do I go about finding a, b and c?

    I've tried subbing back into the equation but it ends up getting far too complicated
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Aug 2009
    Posts
    24
    (z-2)(z+2-i)(z+2+i)=0
    (z-2)((z+2)^2-i^2)=0
    z^3+2z^2-3z-10=0
    Follow Math Help Forum on Facebook and Google+


/mathhelpforum @mathhelpforum