Answer:
BD
AC
SN       (might not be one)
AB
Step-by-step explanation:
 
        
             
        
        
        

Differentiate both sides wrt  :
:

By the chain rule, we get


Solve for  :
:


 
        
             
        
        
        
-3, 3, 5.
https://www.wolframalpha.com/input/?i=%28x%5E3%29-%285x%5E2%29-9x%2B45%3D0
 
        
             
        
        
        
4 - 2(x + 3) = 5
4 - 2x - 6 = 5
-2x - 2 = 5
-2x = 5 + 2
-2x = 7
x = -7/2 or = -3 1/2