SOLUTION: a circle is defined by the following equation: 2x^2+2y^2+28x+80=0 what are the coordinates of its center

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Question 308671: a circle is defined by the following equation:
2x^2+2y^2+28x+80=0
what are the coordinates of its center
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Complete the square in x and y.
2x%5E2%2B2y%5E2%2B28x%2B80=0
%282x%5E2%2B28x%29%2B%282y%5E2%29%2B80=0
%28x%5E2%2B14x%29%2B%28y%5E2%29%2B40=0
%28x%5E2%2B14x%2B49%29%2B%28y%5E2%29%2B40=49
%28x%2B7%29%5E2%2B%28y-0%29%5E2=9
Compare to the general equation of circle with radius R and center (h,k),
%28x-h%29%5E2%2B%28y-k%29%5E2=R%5E2
h=-7
k=0
+R=3+