Results 1 to 2 of 2

Math Help - intersection

  1. #1
    Member
    Joined
    Aug 2009
    Posts
    211

    intersection

    the question is:
    the parabola with equation y = 2x^2 + 4x - 8 intersects the line y + kx + 4k = 0 where k is a constant.
    show that any points of intersection have x coordinates that satisfy 2x^2 + (k + 4)x + 4(k - 2) = 0

    how would you show this? thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor Amer's Avatar
    Joined
    May 2009
    From
    Jordan
    Posts
    1,093
    Quote Originally Posted by mark View Post
    the question is:
    the parabola with equation y = 2x^2 + 4x - 8 intersects the line y + kx + 4k = 0 where k is a constant.
    show that any points of intersection have x coordinates that satisfy 2x^2 + (k + 4)x + 4(k - 2) = 0

    how would you show this? thanks
    when the two curves intersect they have the same x,y cordinates so

    y=2x^2+4x-8

    y=-kx-4k

    -kx-4k = 2x^2 +4x-8

    2x^2 +4x+kx-8+4k=0

    take factors

    2x^2 +x(k+4) + 4(k-2)=0
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Self intersection
    Posted in the Geometry Forum
    Replies: 3
    Last Post: August 1st 2010, 04:15 AM
  2. The intersection of x and ln(x)^p, where p>1
    Posted in the Calculus Forum
    Replies: 2
    Last Post: November 24th 2009, 08:06 AM
  3. Replies: 2
    Last Post: October 19th 2009, 02:47 AM
  4. Another intersection:
    Posted in the Calculus Forum
    Replies: 1
    Last Post: June 6th 2008, 10:26 PM
  5. intersection
    Posted in the Calculus Forum
    Replies: 4
    Last Post: February 11th 2008, 08:20 AM

Search Tags


/mathhelpforum @mathhelpforum