Results 1 to 11 of 11

Math Help - Quadratic equation

  1. #1
    Member
    Joined
    Oct 2008
    Posts
    221

    Post Quadratic equation

    A quadratic equation x^2 + bx + c = 0 has complex roots 3+6i and 3-6i. Find the values of b and c.

    Thank you for any help!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by live_laugh_luv27 View Post
    A quadratic equation x^2 + bx + c = 0 has complex roots 3+6i and 3-6i. Find the values of b and c.

    Thank you for any help!
    hint: the coefficients of the x-squared term in the quadratic is 1, thus the quadratic is given by (x - r_1)(x - r_2), where r_1 and r_2 are the two roots of the equation
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Oct 2008
    Posts
    221
    Quote Originally Posted by Jhevon View Post
    hint: the coefficients of the x-squared term in the quadratic is 1, thus the quadratic is given by (x - r_1)(x - r_2), where r_1 and r_2 are the two roots of the equation

    So, would you do (1-(3+6i )) and (1-(3-6i))??
    Follow Math Help Forum on Facebook and Google+

  4. #4
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by live_laugh_luv27 View Post
    So, would you do (1-(3+6i )) and (1-(3-6i))??
    i have no idea how you got that

    to follow up on what i said, start with (x - 3 - 6i)(x - 3 + 6i)

    now multiply out and you can find b and c
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Oct 2008
    Posts
    221

    Smile

    Quote Originally Posted by Jhevon View Post
    i have no idea how you got that

    to follow up on what i said, start with (x - 3 - 6i)(x - 3 + 6i)

    now multiply out and you can find b and c

    Thank you so much for your help!!
    Follow Math Help Forum on Facebook and Google+

  6. #6
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by live_laugh_luv27 View Post
    Thank you so much for your help!!
    you're welcome

    state your answer when done
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Member
    Joined
    Oct 2008
    Posts
    221
    Quote Originally Posted by Jhevon View Post
    you're welcome

    state your answer when done
    b = -9, c=45
    Follow Math Help Forum on Facebook and Google+

  8. #8
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by live_laugh_luv27 View Post
    b = -9, c=45
    b is incorrect
    Follow Math Help Forum on Facebook and Google+

  9. #9
    Member
    Joined
    Oct 2008
    Posts
    221
    -6 !!!!!!!!!!!
    Follow Math Help Forum on Facebook and Google+

  10. #10
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by live_laugh_luv27 View Post
    -6 !!!!!!!!!!!
    um, yes...!!!!!!!!!!!!
    Follow Math Help Forum on Facebook and Google+

  11. #11
    Member
    Joined
    Oct 2008
    Posts
    221
    Quote Originally Posted by Jhevon View Post
    um, yes...!!!!!!!!!!!!

    thanks again for your help
    I appreciate it
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Quadratic equation
    Posted in the Algebra Forum
    Replies: 2
    Last Post: October 16th 2011, 08:03 AM
  2. Quadratic equation
    Posted in the Algebra Forum
    Replies: 5
    Last Post: March 16th 2011, 11:27 AM
  3. Replies: 3
    Last Post: April 25th 2010, 04:53 PM
  4. Quadratic Equation
    Posted in the Algebra Forum
    Replies: 2
    Last Post: October 14th 2009, 06:34 AM
  5. quadratic equation
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 15th 2008, 05:06 AM

Search Tags


/mathhelpforum @mathhelpforum