$54 is your answer
You multiply $12.00 by 4 packs of pens and then add $6.00 for the pencils.
        
             
        
        
        
-11 = a + 7   Given
-7        -7    Subtract 7 on each side to cancel out +7 and isolate variable
-18 = a        Answer
Prove. 
-11 = -18 + 7    Plug in variable value
-11 = -11
True.
 
        
                    
             
        
        
        
Answer:
hope it's help you ok have a good day
 
        
                    
             
        
        
        
The answer in simplest form would be 1/6