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Homework Help: GRE Sample Question, explanation? Thanks!

  1. Mar 5, 2010 #1
    blu_ifxynot.gif

    The correct answer is (1/y) - (1/xy) but i don't understand why

    What does the sum of xy not equaling zero imply that we can do to the equation to solve it?
     
  2. jcsd
  3. Mar 5, 2010 #2

    Mark44

    Staff: Mentor

    If xy != 0, then neither x nor y = 0.

    Rewrite (x - 1)/(xy) as two separate fractions. What do you get?
     
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