Question

find the center and radius of the circle: (x + 9)^2+(y + 5)^2 = 100
a. (9,5); 10
b. (-9,-5); 10
c. (-5,-9); 100
d. (5,9); 100

Explanation:

Step1: Recall the standard form of a circle equation

The standard - form of a circle equation is $(x - a)^2+(y - b)^2=r^2$, where $(a,b)$ is the center of the circle and $r$ is the radius.
The given equation is $(x + 9)^2+(y + 5)^2=100$, which can be rewritten as $(x-(-9))^2+(y - (-5))^2 = 10^2$.

Step2: Identify the center and radius

For the equation $(x-(-9))^2+(y - (-5))^2 = 10^2$, the center $(a,b)$ is $(-9,-5)$ and the radius $r = 10$.

Answer:

B. (-9,-5); 10