Find the coordinates of the center and the radius of a circle with and equation of:

Question

a. x^2 + 2root7x +7 + (Y-root 11)^2 =11
b. x^2 -12x + 84 =-y^2 + 16y

Answer 1

a. Clarify Eq.

b. x^2-12x=84 -y^2+16y.
x^2-12x+(-12/2)^2+y^2-16y+(-16/2)^2 = -84+36+64.
x^2-12x+36+y^2-16y+(-16/2)^2 = -84.
x^2-12x+36+y^2-16y+64 = -84+36+64.
(x-6)^2+(y-8)^2 = 16.

C(6.8).

r^2 = 16.
r = 4.