The answer to this should be a-8b+13c
a - {4b - [a - (5b - c) + 3c - (a - b - 9c)]} 
=a - {4b - [a - 5b + c + 3c - a + b + 9c]} 
=a - {4b - [- 4b+ 13c]} 
=a - {4b + 4b -13c} 
=a - 8b + 13c 
Hope this helped :)
Have a great day
        
             
        
        
        
Is there supposed to be a picture??
But to answer ur question when ur referring to x your referring to 1 hope this helps
        
             
        
        
        
Answer:
168 cm.
Step-by-step explanation:
If each book has an equal distance of 12 cm and total books are (20-6) = 14
then, total distance is (12*14) = 168.
I hope this is correct. Feel free to correct me if I'm wrong.
 
        
             
        
        
        
Answer:
y+4= -3(x+8)
Step-by-step explanation:
 
        
             
        
        
        
I think it is the fourth one