Question

The equation $x^2 + 6x + y^2 + 6y = 18$ represents a circle. What is its center?

Answer 1

Center = (-3, -3)

Explanation:

`(x-h)^2+(y-k)^2=r^2\\\\Center=(h,k)`

`x^2+6x+y^2+6y=18\\(x^2+6x \,\,\,\,\,\,\,) + (y^2+6y\,\,\,\,\,\,\,)=18\\\\(6)/(2) =(3)^2=9\,\,\,\,\,\,\,\,\,\,\,\,\,\, (6)/(2)=(3)^2 =9\\\\(x^2+6x+9)+(y^2+6y+9)=18+9+9\\(x+3)^2+(y+3)^2=36\\\\Center=(-3,-3)`