Answer:
-7x + 24
Explanation:
(13x + 30) - (20x + 6)
13x + 30 - 20x - 6
-7x + 30 - 6
-7x + 24
        
             
        
        
        
C= 20-0.75x
c= 20-0.75(9)
c= 20-6.75
c= 13.25
Here c is the amount of change and x is the number of books bought.
The customer's change will be $13.25
        
                    
             
        
        
        
Answer:
3y -- 6
Step-by-step explanation:
if the largest number is y, then the other two integers would be (y -- 2) and (y -- 4). 
Therefore the sum of the integers would be 
y + (y -- 2) + (y -- 4) = 3y -- 6.