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Math Help - quadratics

  1. #1
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    quadratics

    how can i find the equation for a function that includes the points:

    (0,4) and
    (2,0)

    i was attempting to use substitution or simultaneous equations but it doesn't work cause I can't substitute the y intercept.

    it ends up being 4=c

    so i dont konw what to do
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  2. #2
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    Hello juliak
    Quote Originally Posted by juliak View Post
    how can i find the equation for a function that includes the points:

    (0,4) and
    (2,0)

    i was attempting to use substitution or simultaneous equations but it doesn't work cause I can't substitute the y intercept.

    it ends up being 4=c

    so i dont konw what to do
    I'm not sure what type of equation you're looking for, since you've headed this post "Quadratics". But the simplest equation through two points will be a straight line, which will be of the form y = mx + c.

    So, if we start there, and put in the two pairs of values:

    When x = 0, y = 4. So 4 = 0m + c \Rightarrow c = 4

    When x=2, y=0. So 0 = 2m+4 \Rightarrow m = -2

    So one possible equation is y = -2x + 4.

    If you're looking for a quadratic equation - one of the form y = ax^2 +bx + c - there will be an infinite number passing through just two points, so you'll need more information if you're going to get a single answer.

    Hope that helps.

    Grandad
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