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

Solving Equations

  1. Mar 5, 2009 #1
    I am given 2 equations (for a calculus problem)...
    y(x2 +4)=5 and x2 +y2 -2y=0.
    I know how to solve for y in terms of x for the first equation, but I am seriously stumped on how to get passed:
    y2 -2y=-x2
  2. jcsd
  3. Mar 5, 2009 #2


    User Avatar
    Homework Helper
    Education Advisor
    Gold Member

    We do not see yet how the calculus aspects will be involved, but only your two equations which you wish to solve. The first equation will permit you to find y in terms of x. The second equation will allow you to find x2 in terms of y. One of these will allow you to perform a substitution which will yield an equation more easily managed and solved.

    note that you seem to almost have the right idea with your line at the botton of your post. When you rectify that, you will have something to substitute.
    Last edited: Mar 5, 2009
  4. Mar 6, 2009 #3
    solving for y in the second equation is not difficult. Ever solved quadratic equations??? do you know any formula to solve a quadratic in y?? (x is constant)

    or.... add one to both sides.. do u see anything familiar?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook