The center of a circle is at (2, -5) and it's radius is 12. what is the equation of the circle? a.) (x+2)^2 + (y-5)^2 =24 b.) (x-2)^2 + (y+5)^2 = 24 c.) (x+2)^2 + (y-2)^2 = 144 d.) (x-2)^2 + (y+5)^2 = 144

The equation for a circle is (x-h)^2 +(y-k)^2=r^2
You just have to plug in your coordinates h is the x and k is the y.
The r is radius squared.
so, (x-2)^2+(y-(-5)^2=144
You have to be careful of those tricky negative values. When you distribute the y-(-5) it turns into y+5. 
So your answer is D.

Use a calculator basically