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Homework Help: Solving this equality. Then simple plot.

  1. Dec 8, 2012 #1
    1. The problem statement, all variables and given/known data

    7/2x >= -1/4

    then put it on a number plot.

    2. Relevant equations

    3. The attempt at a solution

    7x/7 >= -2/4 = -1/2

    -1/2 *7/1 = -7/2

    x>= -7/2 and I'm not sure if I'm even correct for that answer, and I have to put it on a number plot.
  2. jcsd
  3. Dec 8, 2012 #2


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    2017 Award

    Staff: Mentor

    How did you get this? You could show your steps to help troubleshooting.
    If that /7 is just a typo: What did you do afterwards?
    The result is wrong.

    Just to make sure: Your original equation is ##\frac{7}{2}x \geq -\frac{1}{4}##, so x is not in the denominator?
  4. Dec 8, 2012 #3


    Staff: Mentor

    We're uncertain as to what you mean by 7/2x. A literal interpretation using operator precedence would be (7/2) * x. Others might incorrectly interpret this as 7/(2x). What did you mean?
  5. Dec 9, 2012 #4
    The way this equality is written is correct.

    So i reworked the problem, and I get this answer instead.

    2* 7/2*x >= -1/4 *2

    7x >= -1/2

    7x/7 >= -1/2 / 7/1

    x>= -1/14

    which on a number plot should be about 0 to wherever (infinity)? including 0.
  6. Dec 9, 2012 #5


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    Homework Helper

    Again, you need to be sure to add brackets where necessary because 7/2*x can be confused as 7/(2x). In this case, I'd just go ahead and write 7x/2.

    What you have is correct and yes, it'll include x=0 and yes it'll go all the way to infinite. You can try it out for yourself as well! Plug in x=0 for
    7x/2 >= -1/4
    And see if the inequality holds.
  7. Dec 9, 2012 #6
    Yes it holds.

    and agreed 7x/2,

    thanks for all the help.
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