Question

Find the center and radius of (x + 9)^2 + (y + 6)^2 = 9.

a:
(-6, 9); 3

b:
(-9, -6); 3

c:
(9, 6); 3

d:
(-6, -9); 9

Answer 1

To find the center solve for x and y:

x + 9 = 0

x = -9

y + 6 = 0

y = -6

So the center is (-9, -6).

The radius is the square root of 9, which is 3.

So the answer is Option B.

Answer 2

you can do this by comparing your equation to the general form of equation of a circle

( x - a)^2 + (y - b)^2 = r^2 where (a,b) is the centre and r = radius:-
(x + 9)^2 (y + 6)^2 = 9

so (a,b) = (-9,-6) and r = 3

so the answer is B