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Homework Help: Simplify each expression: 2/1+y-2 /2x^3+x

  1. Aug 28, 2011 #1
    1. The problem statement, all variables and given/known data

    2/1+y-2 /2x^3+x its all over top of 2x^3+x

    2. Relevant equations

    3. The attempt at a solution

    should i multiply the top by 1+y, like the 2 and the -2.
  2. jcsd
  3. Aug 28, 2011 #2
    can you use parentheses to make this clearer?
  4. Aug 28, 2011 #3
    Picture0006.jpg heres a picture of it its d)
    Last edited: Aug 28, 2011
  5. Aug 28, 2011 #4
    you have [tex] \frac{\frac{2}{1+y}-2}{2x^3+x} [/tex]

    next you should do [tex] \frac{\frac{2}{1+y}-\frac{2(1+y)}{(1+y)}}{2x^3+x} [/tex]
  6. Aug 28, 2011 #5
    so would this be the final answer. -2y/2x^3+x
  7. Aug 28, 2011 #6
    I think you copied the problem wrong! And no that would not be the answer, you dropped a (1+y) somewhere.
  8. Aug 28, 2011 #7
    sorry im feeling a little stressed i got to 2y/1+y/2x^3+x I've forgotten how to do everything lol.
  9. Aug 28, 2011 #8
    For problem d, [tex] \frac{\frac{2}{1+y}-2}{y} [/tex]
    Start the same way as before with [tex] \frac{\frac{2}{1+y}-\frac{2(1+y)}{(1+y)}}{y} [/tex]

    which becomes [tex] \frac{\frac{2y}{1+y}}{y} [/tex]

    then remember the denominator "y" is actually [tex] \frac{y}{1} [/tex]
    so you have [tex] \frac{\frac{2y}{1+y}}{\frac{y}{1}} [/tex]

    and to divide to fractions you multiply by the reciprocal like this: [tex] \frac{2y}{(1+y)}(\frac{1}{y}) [/tex]

    then just cancel a y from the top and bottom and you're done
  10. Aug 28, 2011 #9
    god I wrote it down wrong thanks.
  11. Aug 28, 2011 #10
    so that would make it 2/y^2
  12. Aug 28, 2011 #11
    eek! no.
    its [tex] \frac{2y}{y(1+y)} [/tex]

    which gives [tex] \frac{2}{1+y} [/tex]
  13. Aug 28, 2011 #12

    Ray Vickson

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    Science Advisor
    Homework Helper

    No: you have written [tex]\frac{-2y}{2x^3} + x[/tex]. Did you mean to write
    [tex]\frac{-2y}{2x^3 + x}?[/tex] If so, then USE BRACKETS, like this: -2y/(2x^3+x). Isn't that simple? It makes everything clear and removes all confusion.

  14. Aug 28, 2011 #13
    that was pointless...
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