Question

For the polynomial function ƒ(x) = 9 − x2, find all local and global extrema.

No local extrema exist.
No global extrema exist.
The only extrema point is (0, 9).
The local and global extrema are: (-3, 0), (3, 0) and (0, 9).

Answer 1

Have you considered drawing it?
Have you considered the first derivative?