Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Solving Rational Equations

  1. Oct 13, 2011 #1
    1. The problem statement, all variables and given/known data


    In the picture above, I solved the rational equation using two different methods. In the first method I got x = 1 and in the second method I got x = 4/3. Which answer is correct or are both of them incorrect? Thanks.
  2. jcsd
  3. Oct 13, 2011 #2


    Staff: Mentor

    If you're going to do your work on paper, and then take a picture of it and upload it, at least do us the courtesy of
    1) providing a reasonably decent picture
    2) providing a picture that is oriented the right way
  4. Oct 13, 2011 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    The rational equation is:
    [itex]\displaystyle \frac{3}{x+2}-\frac{1}{x}=\frac{1}{5x}\,.[/itex]​

    It's easy to check by plugging in the answers.

    [STRIKE]Explain in more detail how you arrived at those answers so we can help you.[/STRIKE]

    Added in edit:

    Never mind. You do show your work in a hard to read sideways image.

    The first method is wrong because you failed to multiply the right side by x(x+2). You must multiply BOTH SIDES of the equation by the same thing.

    The second method was OK. You multiplied both sides by an extra x, which gave you an extraneous solution. x=4/3 is correct.
    Last edited: Oct 13, 2011
  5. Oct 13, 2011 #4
    EDIT: Yup, 4/3 is the correct answer. Thanks for the help.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook