Question

What is the equation of a circle with center (2,-8) and radius 9?

Answer 1

x2+y2-4x+16y-13

Explanation:

center (h,k)=2,-8

radius(r)=9

we know

(x-h)2+(y-k)2=r2

now insert above given information

(x-2)2+(y+8)2=9×9

Answer 2

9^2= (x+2)^2+(y+8)^2

Explanation:

The equation is r^2=(x+h)^2+(y-k)^2