1)Calculate the product:
21a + 10a - 3a
2)Collect like terms:
28a
Answer: 
28a
        
             
        
        
        
Answer:
56
Step-by-step explanation:
if you multiply the volume by 4, you will get 56
 
        
                    
             
        
        
        
 (a) The team captain wants to know what his teammates eats before a match
Team captain know by taking a survey of teammates
(b) The team captain wants to know who can score most goals against the best player
This can be known by observation of games. so its observational study
(c) The team captain wants to know how praising the affects the teammates performance.
This can be known by experiment 
(d) The team captain wants to know what other sports teammates play
This can be known by observation of games. so its observational study
 
        
                    
             
        
        
        
Answer: No, it would be 2/5.
Step-by-step explanation: 2 1/4 - 6/7 is equal to about 1.4 when rounded to the nearest tenth. 1.4 as a fraction would be 4/10. 4/10 is simplified to 2/5 by dividing each number by 2.
 
        
             
        
        
        
That Is The Correct answer ) 20
Hope I Helped 
- Dante