Answer:
(0,0) is a saddle point
(-4,4) is a local maximum
Explanation:

Determine critical points


When x=0

When x=-4

So, we need to check what kinds of points (0,0) and (-4,4) are.
For (0,0)

Therefore, (0,0) is a saddle point since
.
For (-4,4)

Because
and since
, then (-4,4) is a local maximum