Answer:
The answer is 27
Step-by-step explanation:
The reason being, you can solve this 2 ways. 
1) Combine like terms, 7a-4a = 3a.
Now just substitute (a=9) into 3a. 
3 * (9) = 27. 
2) Or just substitute a = 9 into the original expression. 
7 * (9) - 4 * (9) 
= 63 - 36 = 27
 
        
                    
             
        
        
        
-96-(-86)     -10     -2
------------=  ------= -----= -2
  82-87        -5        1
        
             
        
        
        
Answer:
The unit rate is 32/25 Walls per gallons.
Step-by-step explanation:
Gallons of paint used by Martin =  5/8 gallons
Portion of wall Martin wants to paint in pints = 4/5 wall.
Rate at which Martin paints the wall: Rate =  Portion of wall covered/Paints Used.
Rate = 4/5 Gallons/5/8 Gallons = 32/25 Wall Gallons.
 
        
             
        
        
        
Answer:
Step-by-step explanation:
x² + 9x+8 = (x+1)(x+8)