nvm maybe the last one lol
Answer:
D.
Step-by-step explanation:
The point must be a critical point but it could be a saddle point. If the point is a saddle point it would not be neither a maximum nor a minimum. So it must be critical but it does not follow directly that it has a local maximum or local minimum.
Therefore D. (a,b) would be a candidate, but is not necessarily a maximum or minimum. It could be a saddle.
Attached solutions and work.
Answer: 
Step-by-step explanation:

a = base
h = height

Solve the parentheses squared first.

2 and 36 can be simplied
2/2=1
36/2=18


Rounded to the nearest whole number... 
n would equal <em>-33</em>.
<em>n=-33</em>