Answer:
21x²
Step-by-step explanation:
hopefully A is a typo
 
        
                    
             
        
        
        
Answer: 
x= y+2/3+4
Step-by-step explanation:
 
        
             
        
        
        
Answer:
33
Step-by-step explanation:
The base/square:
3*3 = 9
The sides:
(3*4)/2 = 6
4 sides:
6*4 = 24
Total:
24+9=33
 
        
             
        
        
        
If the ratio is 4:3  divide the larger can by 4  which in a)  is  25 then multiply by 3 to get surface area of smaller can which would be 75 square inches.  
In part b) do the same so 150 divided by 4 is 37.5  multiplied by 3  is 112.5 cubic inches. 
It doesn't matter if it is surface area or volume you still use the same ratio of 4:3