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Thread: Quadratics

  1. #1
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    Quadratics

    In the xy-plane, the graph of y =2x2 −15x intersects the graph of y=x atthe points (0, 0) and (a, a) . What is the value of a ? D

    Do I factor out first?

    Thanks
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  2. #2
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    Re: Quadratics

    $2x^2 - 15x = x$

    solve for x
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  3. #3
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    Re: Quadratics

    Quote Originally Posted by allo95 View Post
    In the xy-plane, the graph of y =2x2 −15x intersects the graph of y=x atthe points (0, 0) and (a, a) . What is the value of a ? D

    Do I factor out first?

    Thanks
    Actually I'd write it slightly different: We know that (x, y) = (a, a) for some value of a. So y = 2x^2 - 15x becomes a = 2a^2 - 15a

    -Dan
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    Re: Quadratics

    Thanks for replies. However, still not sure how to solve it.
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  5. #5
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    Re: Quadratics

    $2a^2 - 15a = a$

    $2a^2 - 16a = 0$

    $2a(a-8) = 0$

    so, what is the non-zero value of $a$?
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  6. #6
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    Re: Quadratics

    8! Thanks!!!
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