Results 1 to 6 of 6

Thread: Quadratic Equations

  1. #1
    Junior Member
    Joined
    Sep 2009
    Posts
    40

    Quadratic Equations

    Write down the quadratic equation whose roots are 2/3 and -3/4 expressing your answer without fractions.
    Do I need to find the sum and the product of the roots?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Grandad's Avatar
    Joined
    Dec 2008
    From
    South Coast of England
    Posts
    2,570
    Hello deltaxray
    Quote Originally Posted by deltaxray View Post
    Write down the quadratic equation whose roots are 2/3 and -3/4 expressing your answer without fractions.
    Do I need to find the sum and the product of the roots?
    You could do, but it's probably easier just to re-write each of the equations
    x=\frac23 and x = -\frac34
    in the form px+q = 0. Then multiply these 'px+q' expressions together to obtain a quadratic equation in the familiar form ax^2 + bx + c =0.

    Can you do that?

    Grandad
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Sep 2009
    Posts
    40
    Is the answer 12x^2+x-6=0 ?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Apr 2005
    Posts
    13,725
    Thanks
    548
    Do 2/3 and -3/4 satisfy that equation?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Super Member dhiab's Avatar
    Joined
    May 2009
    From
    ALGERIA
    Posts
    521
    a\left(x-\frac{2}{3}\right)\left(x+\frac{3}{4}\right)=0<br />
and a\neq0
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Junior Member
    Joined
    Nov 2009
    Posts
    63
    let p=\frac {2}{3} and q=- \frac {3}{4}.
    there are 2 method to make a new equation with roots p and q,
    1. (x-p)(x-q)=0 or
    2. x^2 - (p+q) x + (pq) =0
    those 2 method has the same output.
    ......good luck......
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. quadratic equations
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 6th 2010, 05:20 PM
  2. quadratic equations
    Posted in the Algebra Forum
    Replies: 3
    Last Post: August 14th 2010, 06:01 PM
  3. Replies: 1
    Last Post: June 12th 2008, 09:30 PM
  4. quadratic equations
    Posted in the Algebra Forum
    Replies: 3
    Last Post: May 18th 2008, 10:20 AM
  5. Quadratic Equations Help
    Posted in the Algebra Forum
    Replies: 1
    Last Post: January 13th 2008, 08:43 PM

Search Tags


/mathhelpforum @mathhelpforum