Question

Calculate the center and radius of the circle by completing the square of the following equation.

x2+y2+8x−6y−11=0 (1 point)

Center: (4, −3) , Radius: 6


Center: (8, −6) , Radius: 3


Center: (−4, 3) , Radius: 6


Center: (−8, 6) , Radius: 3

Answer 1

x^2 + y^2 + 8x − 6y − 11 = 0
=> (x^2 + 8x) + (y^2 − 6y) = 11
=> (x+4)^2 − 16 + (y−3)^2 − 9 = 11
=> (x+4)^2 + (y−3)^2 = 36

Center = (−4, 3), Radius = 6.