Answer:

Step-by-step explanation:
Expression for the rectangular area and perimeter are, respectively:


After some algebraic manipulation, area expression can be reduce to an one-variable form:


The first derivative of the previous equation is:

Let the expression be equalized to zero:


The second derivative is:

According to the Second Derivative Test, the critical value found in previous steps is a maximum. Then:

The maximum area is:


 
        
                    
             
        
        
        
I believe x is 104 but I don’t know about y
        
             
        
        
        
Answer:
C
Step-by-step explanation:
It looks to me possibly C
hope it helps you
 
        
                    
             
        
        
        
15% of 12 is 1.8
Hope I could help!