Results 1 to 3 of 3

Math Help - Completing the Square and Quadratic Formula..NEED HELP PLEASE

  1. #1
    Junior Member
    Joined
    Sep 2008
    Posts
    40

    Completing the Square and Quadratic Formula..NEED HELP PLEASE

    Solve the formula for y?
    x^2+y^2=r^2
    I subrtracted x^2 from both sides and then divided y^2 on both sides...am I on the right track or totally off?

    Change the equation to Quadratic Form and then solve using any method?

    x(2x+1)/x-4=36/x-4
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Apr 2008
    Posts
    1,092
    1. Given x^2 + y^2 = r^2:

    Subtract x^2 from both sides.
    y^2 = r^2 - x^2

    Take the square root of both sides.
    y = \pm\sqrt{r^2 - x^2}

    2. Given \frac{x(2x + 1)}{x - 4} = \frac{36}{x - 4}:

    Multiply both sides by x - 4.
    x(2x + 1) = 36

    Distribute x and subtract 36 from both sides.
    2x^2 + x - 36 = 0

    Solve using the quadratic formula.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member
    Joined
    Sep 2007
    Posts
    528
    Awards
    1
    Here are the general rule. If your quadratic equation is in the form ax^2+bx+c =0, then for:

    Completing the square - a\left[\left(x + \frac{b}{2a}\right)^2 - \left(\frac{b}{2a}\right)^2 + \frac{c}{a}\right]=0.

    Quadratic equation - x = \frac{-b \pm \sqrt{b^2-4ac}}{2a}.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: January 12th 2012, 05:42 AM
  2. Quadratic and Completing square
    Posted in the Algebra Forum
    Replies: 6
    Last Post: October 25th 2010, 04:40 PM
  3. Completing the Square vs Quadratic Formula
    Posted in the Algebra Forum
    Replies: 3
    Last Post: July 10th 2010, 07:33 AM
  4. quadratic formula/completing the square?
    Posted in the Pre-Calculus Forum
    Replies: 6
    Last Post: June 10th 2009, 02:27 PM
  5. Completing the Square (Quadratic Polynomials)
    Posted in the Math Topics Forum
    Replies: 2
    Last Post: June 3rd 2009, 04:58 AM

Search Tags


/mathhelpforum @mathhelpforum