Results 1 to 4 of 4

Math Help - absolute value on both side of equation

  1. #1
    Newbie
    Joined
    Aug 2010
    Posts
    5

    Post absolute value on both side of equation

    I solved this absolute value equation and I am confuse about the answer given in the book for this question, the answer in the book is x > = 0 or x = -2/3 please tell me how can I get this answer from the following solution. Please tell the method which should be true for all such type of questions.
    absolute value on both side of equation-img.jpg
    solving the second part we come to know that the right part of this is also true for all real numbers.
    Please help.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,610
    Thanks
    1574
    Awards
    1
    Please state the original problem without using an image.
    As is, it appears as if you have jumped in the middle of a solution.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Aug 2010
    Posts
    5
    the original problem that i am trying to solve is |3x^2 + 2x|= x|3x+2|
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,610
    Thanks
    1574
    Awards
    1
    First I would notice that \left| {3x^2  + 2x} \right| = |x|\left| {3x + 2} \right|.
    Then we have to solve  |x|\left| {3x + 2} \right|=x|3x+2|

    Therefore we have three problems to consider.

    x < \frac{{ - 2}}{3}\, \Rightarrow \,( - x)( - 3x - 2) = x( - 3x - 2).

    \frac{{ - 2}}{3} \leqslant x < 0\, \Rightarrow \,( - x)(3x + 2) = x(3x + 2).

    0 \leqslant x \Rightarrow \,(x)(3x + 2) = x(3x + 2).
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: December 1st 2011, 09:56 PM
  2. Replies: 0
    Last Post: November 13th 2011, 02:32 PM
  3. Normal distribution beams laid side by side
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: March 12th 2011, 03:05 AM
  4. Moving variable to other side of equation
    Posted in the Algebra Forum
    Replies: 4
    Last Post: October 16th 2008, 03:32 AM
  5. Replies: 1
    Last Post: September 14th 2008, 12:25 PM

Search Tags


/mathhelpforum @mathhelpforum