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Homework Help: Sketching Absolute value graphs

  1. Mar 8, 2009 #1
    1. The problem statement, all variables and given/known data
    I previously left some absolute value questions which contained a few simple equations and equalities.

    i have a further question when it comes to slightly more complicated Absolute statements.

    Sketch the graph of y = 2|x-1| - 3|x+1| + 3x + 1



    2. Relevant equations
    /


    3. The attempt at a solution
    ???
     
  2. jcsd
  3. Mar 8, 2009 #2

    tiny-tim

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    Hi w0lfed! :smile:

    Do it in three bits …

    x ≤ -1, -1 ≤ x ≤ 1, x ≥ 1 :wink:
     
  4. Mar 8, 2009 #3
    i think i need a lil more help...?
    do we just make the absolute values negative for x=< - 1 or is there more to it like a sign table?
    my lecturer just threw about 20 methods at us in 2 mins and i get quite confused because i try and combine em all and everyone says something else :S
     
  5. Mar 8, 2009 #4

    tiny-tim

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    eg for x = -7, |x + 1| = |-7 + 1| = |-6| = 6 …

    and generally for x ≤ -1, |x + 1| = -(x + 1) :smile:
     
  6. Mar 8, 2009 #5
    ok cool, i get that, but now do we make it positive or negative for -1 =< X =< 1

    and then also...do we just leave and solve the values of X which are not absolute eg 3x like we would normally do

    thanks very much Tiny Tim for you help
     
  7. Mar 8, 2009 #6

    tiny-tim

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    Hi w0lfed! :smile:

    look at each one separately … if it would be negative, multiply it by -1 …

    and yes, leave the others like you normally would. :wink:
     
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