The variable is b, the coefinet is 1/3 
remember
ab-ac=a(b-c)
1/3b-1/3=1/3(b-1)
there, factored
        
             
        
        
        
Answer:
Step-by-step explanation:
(51 miles)/(3 gal) = 19 miles/gal
 
        
                    
             
        
        
        
First, you should do the product first:
(-4.7)* (7.021)= -32.9987
Then, let's do the subtraction:
(-5.12)- (-32.9987)
= (-5.12)+ 32.9987
= 27.8787
Final answer: 27.8787
Hope this would help~
        
                    
             
        
        
        
See tha attached pdf file and let me know how useful this answer is.