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MATH HELP!!

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

  1. DiRect

    DiRect Regular member

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    |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

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    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

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    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

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    Yep 100% right, its been awile since ive done these but its definitely x > 1.
     

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