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Math Help - Quadratic Equations

  1. #1
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    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?
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  2. #2
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    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
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  3. #3
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    Is the answer 12x^2+x-6=0 ?
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  4. #4
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    Do 2/3 and -3/4 satisfy that equation?
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  5. #5
    Super Member dhiab's Avatar
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    a\left(x-\frac{2}{3}\right)\left(x+\frac{3}{4}\right)=0<br />
and a\neq0
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  6. #6
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    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......
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