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Anonymous
Anonymous asked in Science & MathematicsMathematics · 1 decade ago

Help with quadratic function problem?

Having trouble with this problem

find a quadratic function who x intercepts are -3 and 1 and a is 2

7 Answers

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  • 1 decade ago
    Favorite Answer

    2(x^2+2x-3)=y

    x=-3

    (x+3)=0

    x=1

    (x-1)=0

    (x+3)(x-1)=0

    (x^2+2x-3)=y Times by 2.

    2(x^2+2x-3)=y

    Answer is 2x^2+4x-6=y

  • Anonymous
    1 decade ago

    If -3 is an x-intercept, then the function has (x+3) as a factor (plugging x=-3 will give f(-3)=0).

    Another factor is (x-1) for our other intercept x=1.

    Multiplying these two factors gives a coefficient of 1 for x² so you need to double it to get a=2.

    Answer: f(x) = 2(x+3)(x-1) = 2x² + 4x - 6.

  • 1 decade ago

    The answer is 2(x--3)(x-1)=2x^2+4x-6.

  • 1 decade ago

    you would take x=-3 and x=1

    so y=(x+3)(x-1)

    then y=x^2 -x +3x -3

    y=(x^2)+2x-3

    but we need a to equal 2 so we times it all by 2 and get

    y=2(x^2)+4x-6

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  • 1 decade ago

    y=2x^2 + 4X - 6

  • 1 decade ago

    you have to use the quadratic equation:

    x= the opposite of b plus or minus radical (square root) b squared minus 4 ac over 2a. (hey!)

    a is the first number so you plug that in to the 4ac and 2a.

  • 1 decade ago

    the a is a 2??? *boggles*

    as in the y = Ax^2 + Bx + C .... the A = 2?

    then (-B +/- SQRT(B^2 - 4AC))/2A = -3 and 1

    B = 4

    SQRT(16 - 8C) = 2

    16 - 8C = 4

    C = 3/2

    y = 2x^2 + 4X + 3/2

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