1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

MATH HELP!!

Discussion in 'All other topics' started by DiRect, Jun 16, 2007.

  1. DiRect

    DiRect Regular member

    Joined:
    Jul 4, 2004
    Messages:
    283
    Likes Received:
    0
    Trophy Points:
    26
    |3x + 1| > |2x + 2|

    This is what I have so far:

    Case 1:

    positive = positive
    3x + 1 > 2x + 2
    x > 1

    BUT
    3x + 1 > 0 therefore x > -1/3
    BUT
    2x + 2 > 0 therefore x > -1

    FINAL CONDITION: x > -1

    Case 2:

    negative = positive

    -3x - 1 > 2x + 2
    -5x > 3
    x < -3/5
    BUT
    3x + 1 < 0 therefore x < -1/3
    BUT 2x + 2 > 0 therefore x > -1

    FINAL CONDITION: -1 < x < -1/3

    Case 3:

    positive = negative

    3x + 1 > -2x - 2
    5x > -3
    x > -3/5
    BUT 3x + 1 > 0 therefore x > -1/3
    BUT 2x + 2 < 0 therefore x < -1

    FINAL CONDITION:

    I am confused for this final condition, because if you graph it on a number line, you'll get a domain for x > -1/3 but than for this FINAL CASE x < -1 which confuses me because it doesn't intersect with the other domains of X in that final case, so what would the final condition for that case be and what would the FINAL CONDITION for the whole question be?

    Thank you for any and all help ;)
     
  2. 11jstedm

    11jstedm Member

    Joined:
    May 30, 2007
    Messages:
    16
    Likes Received:
    0
    Trophy Points:
    11
    dude ur making this WAY more complex then it needs to be. the answer IS x > 1.
     
    Last edited: Jun 16, 2007
  3. DiRect

    DiRect Regular member

    Joined:
    Jul 4, 2004
    Messages:
    283
    Likes Received:
    0
    Trophy Points:
    26
    That is the way I was thought :S because sometimes in absolute value graphs, certain branches DO NOT intersect, and you have to do this to find out which region is below or above which region etc. How did you arrive at the answer x > 1?

    Thanks for your help :)
     
  4. canuckerz

    canuckerz Regular member

    Joined:
    Dec 25, 2006
    Messages:
    2,140
    Likes Received:
    0
    Trophy Points:
    46
    Yep 100% right, its been awile since ive done these but its definitely x > 1.
     

Share This Page