Which part do you need help on?
        
                    
             
        
        
        
Since A (3,4) A’(9,12)
You can see 3*3=9
Therefor it was enlarged by 3times 
Scale factor of 3
        
             
        
        
        
Answer:
The expression represents the total cost of the bag which contain x number of goby and x number of shrimp.
Step-by-step explanation:
Each goby fish costs $15 and each shrimp costs $10.
 Each bag has an equal number of goby fish and shrimp.
So. let each bag has x number of goby and x number of shrimp
so, the cost of the bag = 15x + 10x
Take x as a common
so, the total cost = x (15+ 10)
so, the expression represents the total cost of the bag which contain x number of goby and x number of shrimp.