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August 5th, 2016, 10:02 PM   #1
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Unhappy 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
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August 9th, 2016, 07:29 PM   #2
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$\displaystyle 9x^2+9y^2+42x+84y+65=0$

$\displaystyle 9x^2+42x+9y^2+84y=-65$

$\displaystyle (3x+7)^2+(3y+14)^2=-65+49+196=-65+245=180$

$\displaystyle \dfrac{(3x+7)^2}{9}+\dfrac{(3y+14)^2}{9}=\dfrac{18 0}{9}$

$\displaystyle \left(\dfrac{3x+7}{3}\right)^2+\left(\dfrac{3y+14} {3}\right)^2=20$

$\displaystyle \left(x+\dfrac73\right)^2+\left(y+\dfrac{14}{3} \right)^2=20$
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