Results 1 to 6 of 6

Thread: [SOLVED] Absolute Values and Inequalities

  1. #1
    Junior Member
    Joined
    Jan 2009
    Posts
    40

    [SOLVED] Absolute Values and Inequalities

    Follow Math Help Forum on Facebook and Google+

  2. #2
    Junior Member mathhomework's Avatar
    Joined
    Jan 2009
    Posts
    37

    My Answer

    greater than or equal to 0

    x can be any real number, because the absolute value of any number is bigger or equal to 0.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Banned
    Joined
    Aug 2008
    Posts
    530
    Quote Originally Posted by mathhomework View Post
    greater than or equal to 0

    x can be any real number, because the absolute value of any number is bigger or equal to 0.
    $\displaystyle
    |x + 4| \ge 0
    $

    $\displaystyle \Rightarrow x+4 \ge 0$

    $\displaystyle \Rightarrow x\ge -4$ .................................(1)

    OR

    $\displaystyle |x + 4| \ge 0$

    $\displaystyle \Rightarrow -(x+4) \ge 0$

    $\displaystyle \Rightarrow -x\ge 4$

    $\displaystyle
    \Rightarrow x\le -4 ...................................(2)
    $

    from (1) and (2), x can have all real values. So,

    $\displaystyle x\in \mathbb{R}$
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    Jan 2009
    Posts
    40
    I'm sorry, I posted that wrong, it is supposed to be less than or equal to zero.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member mathhomework's Avatar
    Joined
    Jan 2009
    Posts
    37

    My Answer

    x <= -4
    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 tmac11522 View Post
    I'm sorry, I posted that wrong, it is supposed to be less than or equal to zero.
    $\displaystyle |x| \ge 0$ for all real $\displaystyle x$.

    thus, $\displaystyle |x| \le 0$ only makes sense if $\displaystyle |x| = 0$

    thus we want $\displaystyle x + 4 = 0 \implies x = -4$ is our only solution.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Inequalities, Absolute Values on both sides
    Posted in the Algebra Forum
    Replies: 10
    Last Post: Jun 24th 2011, 03:50 AM
  2. [SOLVED] Absolute values
    Posted in the Math Challenge Problems Forum
    Replies: 8
    Last Post: May 14th 2010, 09:10 AM
  3. Replies: 1
    Last Post: Nov 2nd 2009, 12:31 PM
  4. Replies: 8
    Last Post: Jul 16th 2009, 03:45 PM
  5. Inequalities & absolute values
    Posted in the Algebra Forum
    Replies: 1
    Last Post: Oct 19th 2008, 10:44 PM

Search Tags


/mathhelpforum @mathhelpforum