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AS Maths: Finding Coordinates from Simultaneous Equations watch

    • Thread Starter
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    Hi there, im quite stuck on the following question:
    "Find the coordinates of the points of intersection of the given straight lines with the given curves"

    y=2x-12 x^2+4xy-3y^2= -27

    I would like to know how to do it please as im rather confused on this topic!

    Thanks!
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    I think you need to give us the whole question.
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    That is it above! Lol.

    The bold is one equation, the non bold is the other.
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    At the points of intersection, the x- and y-coordinates of the two curves must be equal, which means we can substitute one curve into the other. Since we know that y=2x-12 on the first curve, it seems easiest to sub the y-coordinate of this curve into the equation of the second curve. This gives:
    x^2+4x(2x-12) - 3(2x-12)^2 = -27

    You can then expand and solve this to get the x-coordinates of the points of intersection. The y-coordinates can then be found by substituting the values of the x-coordinates into the first equation.
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    Thanks, will work that out now.
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    (Original post by ~Sparked~)
    That is it above! Lol.

    The bold is one equation, the non bold is the other.
    Sorry before you added the bold, I thought you had just provided the equation of the curve!
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    (Original post by Mr M)
    Sorry before you added the bold, I thought you had just provided the equation of the curve!
    It was my bad, i didnt make it clear enough to begin with. Sorry.
 
 
 
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Updated: September 30, 2010
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