August 5th, 2016, 11:02 PM  #1 
Member Joined: Aug 2016 From: South Korea Posts: 54 Thanks: 0  Analytic Geometry
Help me guys! My answer in this general form 9x^2 + 9y^2 + 42x + 84y + 65 = 0 is (x + 21)^2 + (y +42)^2 = √2140/9 but I think it's wrong.. I don't know anymore 
August 9th, 2016, 08:29 PM  #2 
Global Moderator Joined: Oct 2008 From: London, Ontario, Canada  The Forest City Posts: 7,913 Thanks: 1113 Math Focus: Elementary mathematics and beyond 
$\displaystyle 9x^2+9y^2+42x+84y+65=0$ $\displaystyle 9x^2+42x+9y^2+84y=65$ $\displaystyle (3x+7)^2+(3y+14)^2=65+49+196=65+245=180$ $\displaystyle \dfrac{(3x+7)^2}{9}+\dfrac{(3y+14)^2}{9}=\dfrac{18 0}{9}$ $\displaystyle \left(\dfrac{3x+7}{3}\right)^2+\left(\dfrac{3y+14} {3}\right)^2=20$ $\displaystyle \left(x+\dfrac73\right)^2+\left(y+\dfrac{14}{3} \right)^2=20$ 

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analytic, geometry, pre calculus 
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