The equation of a circle is given as 2x^2 + 2y^2 + 4x + 12y + 6 = 0. What are the center, C, and the radius, r of the circle?
+36915 2x^2 + 2y^2 + 4x + 12y + 6 = 0 divide thru by 2
x^2 + 2x + y^2 + 6y = -6 complete the square for x and y
(x+1)^2 + (y+3)^2 = - 6 +1 + 9
(x+1)^2 + (y+2)^2 = 4
this is a circle equation of the form (x-h)^2 + (y-k)^2 = r ^2 center = (h,k) = ( -1,-2) radius = 2
