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Math Help - Little help please - simultaneous equations

  1. #1
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    Little help please - simultaneous equations

    I'm to solve simultaneous equation :

    y = −3x + 2
    y = 2x2 −7x−4

    I know the what the answer should be but i never seem to get it, so im clearly doing it wrong!
    Any help especially on how to solve it would really be appreciated!
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  2. #2
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    Re: Little help please - simultaneous equations

    Equating the right-hand sides of the two equations gives you a quadratic equation. If you have trouble solving it, please post your solution steps so that we can give you feedback.

    In plain text, it is customary to write x^2 for x^2.
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  3. #3
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    Re: Little help please - simultaneous equations

    Thank's

    Heres one of my attempts...theres been a few!

    0 = 2x^2 - 4x - 6
    ( 2x+3)(x-2)
    2x+3 + 0 and x-2 = 0
    x is -1.5 and x is 2

    Im supposedly to have the answer of -1 and 5 somehow, but no idea how !

    Thanks for any input in advance
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  4. #4
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    Re: Little help please - simultaneous equations

    Quote Originally Posted by tommy68 View Post
    0 = 2x^2 - 4x - 6
    ( 2x+3)(x-2)
    (2x+3)(x-2) = 2x^2 - x - 6 ≠ 2x^2 - 4x - 6.

    If you know the quadratic formula, you should use it.

    Quote Originally Posted by tommy68 View Post
    Im supposedly to have the answer of -1 and 5 somehow
    The solutions are x = -1 and x = 3. The value x = 5 does not fit the original equations.
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  5. #5
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    Re: Little help please - simultaneous equations

    ah i see, thank you very much for the help! Seems i've not been doing it right at all! Back to the drawing board for me!
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