factoring...

Discussion in 'Physics & Math' started by qfrontier, Mar 3, 2002.

  1. qfrontier Captain Of Starship Registered Senior Member

    Messages:
    114
    factoring...another question (edited)

    How would you find the value of x for the quadratic equation of :

    6x^2+3x-2=0

    ps. Ive found a solution but im not sure if its the solution...any help appreciated.

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    Last edited: Mar 10, 2002
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  3. Anton Registered Member

    Messages:
    8
    Hmm..well my calculator does it quite well

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    and finds that the factors are -1.542575695 and 7.582575695 and that the min is non existant (its a parabola so that is a given) and the max is 7. Hope that helps. If u wanted to do it yourself, simply use the quadratic equation:

    x=-b +/- sqrrt(b^2-4ac)
    ---------------------------
    2a

    and use the derivative of the equation to find the max

    -Anton
     
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  5. James R Just this guy, you know? Staff Member

    Messages:
    30,644
    y=-1/3x^2 + 2x + 4

    Take out the -1/3 factor.

    = -1/3 (x^2 - 6x - 12)

    Complete the square.

    = -1/3 (x^2 - 6x + 9 - 12 - 9)

    = -1/3 ((x - 3)^2 - 21)

    Put the -1/3 back in.

    = -1/3 (x - 3)^2 + 7

    The maximum is y=7, which occurs at x=3.
     
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  7. qfrontier Captain Of Starship Registered Senior Member

    Messages:
    114
    great! thx

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    guys!
     

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