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Math Help - graphing a cricle

  1. #1
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    graphing a cricle

    x^2+10x+y^2-10y+46=0

    how do you put that in standard form for a circle?
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  2. #2
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    Quote Originally Posted by danimals24 View Post
    x^2+10x+y^2-10y+46=0

    how do you put that in standard form for a circle?
    Equation of a circle with centre (a,b) and radius r: (x-a)^2 + (y-b)^2 = r^2

    Complete the square for x and y:

    (x+5)^2 = x^2+10x {\color{red} +25} \rightarrow x^2+10x = (x+5)^2 {\color{red} -25}.

    You can do the same with y to give y^2-10y = (y-5)^2 {\color{red} -25}

    Once you've done that collect the constants together and move them over to the right hand side.
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