Results 1 to 3 of 3
Like Tree1Thanks
  • 1 Post By Soroban

Math Help - isolating x when f(x) is a rational function of degree2 / degree1

  1. #1
    Newbie
    Joined
    Sep 2012
    From
    canada
    Posts
    3

    isolating x when f(x) is a rational function of degree2 / degree1

    ex. y = (x^2 + 3) / (x - 1)

    cant seem to isolate the x squared. also the eq. can be rewritten as

    y = (x+1) + (4 / (x-1))

    help would be appreciated
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Sep 2012
    From
    canada
    Posts
    3

    Re: isolating x when f(x) is a rational function of degree2 / degree1

    also, cant use calulus, must solve algebraically
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,547
    Thanks
    539

    Re: isolating x when f(x) is a rational function of degree2 / degree1

    Hello, mzez!

    \text{Solve for }x\!:\;y \:=\: \frac{x^2 + 3}{x - 1}

    We have: . y(x-1) \:=\:x^2+3 \quad\Rightarrow\quad xy - y \:=\:x^2+3  \quad\Rightarrow\quad x^2 - yx + (y+3) \:=\:0

    Quadratic Formula: . x \;=\;\frac{y \pm \sqrt{y^2 - 4(y+3)}}{2}

    . . . . . . Therefore: . x \;=\;\frac{y \pm \sqrt{y^2 - 4y - 12}}{2}
    Thanks from mzez
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Isolating
    Posted in the Algebra Forum
    Replies: 7
    Last Post: August 28th 2011, 12:44 PM
  2. Replies: 2
    Last Post: March 20th 2011, 01:29 AM
  3. Replies: 1
    Last Post: February 17th 2010, 03:05 AM
  4. Replies: 2
    Last Post: September 27th 2009, 08:37 PM
  5. Isolating for x
    Posted in the Calculus Forum
    Replies: 2
    Last Post: March 21st 2008, 10:40 AM

Search Tags


/mathhelpforum @mathhelpforum