18+8x=-2y
18+8x/-2=-2y/-2
-8-4x=y
        
                    
             
        
        
        
Answer: $6000
Step-by-step explanation:
Multiply the cost of the book by the decimal equivalent of 12% (25 x .12).  this equal 3 dollars per book.  2,000 copies of the book were sold, so you would multiply 2000 by 3.  2000 x 3 = 6000
 
        
             
        
        
        
40 is the correct answer for this