what is the answer to the problem i need help with?

Answer:
C
Step-by-step explanation:
Recall the equation for a circle:
[tex](x-h)^2+(y-k)^2=r^2[/tex], where the center is (h,k) and the radius is r.
The given equation is:
[tex](x+5)^2+(y+7)^2=21^2[/tex]
Another way to write this is:
[tex](x-(-5))^2+(y-(-7))^2=21^2[/tex]
Thus, we can see that h=-5 and k=-7.
The center is at (-5, -7).