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Math Help - points of intersections, urgent!!!

  1. #1
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    Question points of intersections, urgent!!!

    Determine the point(s) of intersection algebraically. Then verify your result numerically by creating a table of values for each equation.
    y=2x^2
    y=-2x^2+324
    What I have so far is:
    I set them equal to each other: 2x^2=-2x^2+324
    Then I added 2x^2 to each side: 4x^2=324
    Then I divided each side by 4: x^2=81
    Then I took the square root of each side: x=9.
    Where do I go from here...is that the only point of intersection???
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  2. #2
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    Quote Originally Posted by iheartthemusic29 View Post
    Determine the point(s) of intersection algebraically. Then verify your result numerically by creating a table of values for each equation.
    y=2x^2
    y=-2x^2+324
    What I have so far is:
    I set them equal to each other: 2x^2=-2x^2+324
    Then I added 2x^2 to each side: 4x^2=324
    Then I divided each side by 4: x^2=81
    Then I took the square root of each side: x=9.
    Where do I go from here...is that the only point of intersection???
    Hello,

    that was a real near miss. You wrote:

    Then I divided each side by 4: x^2=81
    Then I took the square root of each side: x=9.
    The correct answer is: | x | = 9 that means: x = 9 or x = -9.

    Now plug in these values into one of the equations. I take the first one (it's easier to calculate):
    x = 9: y = 2*(9)^2 = 162
    x = -9: y = 2*(-9)^2 = 162

    You have two points: (9, 162), (-9, 162)
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