Answer:
(x-3)^2+(y+2)^2=16
Step-by-step explanation:
center (h,k) radius r
(x-h)^2+(y-k)^2=r^2
It's dependent on the context. A book may ask you to find the f'(x) of a function and you may have to use a u sub in your problem which requires you to find the dy/dx of what you substitute. So in this case both would be used.
