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Homework Help: Rearranging to solve an equation (quick question)

  1. Jan 10, 2012 #1
    1. The problem statement, all variables and given/known data

    Say I had x = y-2 / y + 3

    How would I go about rearranging for y= ?

    I cant think how to simplify it down to a single y term.
  2. jcsd
  3. Jan 10, 2012 #2
    If you don't know how to start, just trying playing around with it. My first step would be to get rid of the y+3 in the denominator.
  4. Jan 10, 2012 #3
    Multiply all terms by y.
    You then have a second degree polynomial in y, which can be solved in the usual manner (assuming y does not depend on x).
  5. Jan 10, 2012 #4
    This seems unnecessary to me. One can solve this simply by multiplying and factoring.
  6. Jan 10, 2012 #5


    Staff: Mentor

    I'm assuming you mean x = (y - 2)/(y + 3). What you wrote is actually x = y - (2/y) + 3.

    The lesson is: USE PARENTHESES!
  7. Jan 10, 2012 #6
    Or use LATEX.
  8. Jan 10, 2012 #7


    User Avatar
    Homework Helper

    I'm assuming that bigfooted read the problem as x = y - (2/y) + 3. If it is supposed to be x = (y - 2)/(y + 3) then of course multiplying and factoring would be the way to go.
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