SOLUTION: find the center and the radius of the circle x^2+2x+y^2-6y-6=0

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Question 160277: find the center and the radius of the circle x^2+2x+y^2-6y-6=0
Answer by KnightOwlTutor(293) About Me  (Show Source):
You can put this solution on YOUR website!
The first step you need to do us complete the sqaure
Group the common variables together
(x^2+2x+_)+(y^2-6y+_)=6
Take the middle term and divide by 2 and get 1 square this number
(x^2+2x+1)
Do the same for the y variable
y^2-6y+_)= -6/2=-3 (-3)^2=9

so now the equation looks like
(x^2+2x+1)+(y^2-6y+9)=
Now you have to add 1+9 to the other side of the equation to keep it the same
(x^2+2x+1)+(y^2-6y+9)=6+1+9
Factor both variables
(x+1)^2+(y-3)^2=16
the radius is at (-1,3) Radius is the sqrt of 16 and =4