Results 1 to 3 of 3

Math Help - Another Quadratic Problem

  1. #1
    Newbie
    Joined
    May 2011
    Posts
    6

    Another Quadratic Problem

    I've been trying to figure out this question but i dont know where im going wrong when i plug back in the solutions i get, i get a bunch of wacky numbers...

    question : x^2 + (x + 2) ^2 = 290

    my work:
    = x^2 + (x +2) + (x + 2) = 290
    = 2x^2 + 4x + 4 = 290
    = 2x + 4x - 286 = 0
    = 2 (x^2 + 2x - 143) = 0
    = (x - 11) ( x + 13)
    x = 11
    x = -13 .. why is this wrong?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    A Plied Mathematician
    Joined
    Jun 2010
    From
    CT, USA
    Posts
    6,318
    Thanks
    5
    Awards
    2
    Quote Originally Posted by spadda View Post
    I've been trying to figure out this question but i dont know where im going wrong when i plug back in the solutions i get, i get a bunch of wacky numbers...

    question : x^2 + (x + 2) ^2 = 290

    my work:
    = x^2 + (x +2) + (x + 2) = 290
    = 2x^2 + 4x + 4 = 290
    = 2x + 4x - 286 = 0
    = 2 (x^2 + 2x - 143) = 0
    = (x - 11) ( x + 13)
    x = 11
    x = -13 .. why is this wrong?
    Looks correct to me! Plug those numbers back into your original equation (which you should do as a matter of course), and they both satisfy the original equation.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1
    Quote Originally Posted by spadda View Post
    I've been trying to figure out this question but i dont know where im going wrong when i plug back in the solutions i get, i get a bunch of wacky numbers...

    question : x^2 + (x + 2) ^2 = 290

    my work:
    = x^2 + (x +2) + (x + 2) = 290
    Typo? I'm guessing it is because your working is fine as are both solution
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] quadratic equation, A.P. and G.P. related problem problem
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: August 20th 2011, 09:43 AM
  2. quadratic problem
    Posted in the Algebra Forum
    Replies: 2
    Last Post: March 12th 2011, 10:37 AM
  3. Help on this quadratic problem
    Posted in the Algebra Forum
    Replies: 4
    Last Post: November 4th 2010, 02:36 PM
  4. Quadratic Problem
    Posted in the Algebra Forum
    Replies: 2
    Last Post: May 9th 2009, 01:41 PM
  5. quadratic problem
    Posted in the Algebra Forum
    Replies: 2
    Last Post: February 26th 2009, 02:55 AM

Search Tags


/mathhelpforum @mathhelpforum