Question 763199
x^2 + y^2 + 8x + 6y + 9 = 0
Separate the x's and y's
(x^2 + 8x) + (y^2 + 6y) + 9 = 0
Completing the square on x's
(x^2 + 8x + 4^2) - 4^2
(x + 4)^2 - 16
Completing the square on y's
(y^2 + 6y + 3^2) - 3^2
(y + 3)^2 -9
Putting back into equation:-
(x^2 + 8x) + (y^2 + 6y) + 9 = 0
((x + 4)^2 - 16)+((y + 3)^2 - 9) + 9 = 0
 (x + 4)^2 + (y + 3)^2 -16 -9 + 9 = 0
 (x + 4)^2 + (y + 3)^2 - 16 = 0
 (x + 4)^2 + (y + 3)^2 = 16
Centre (-4, -3) Radius = 4