Respuesta :

daijingyi722
(1) let there be x book and let the total cost be y dollars.
         y=19.25x+40
         y=16x+69.25
(2)  19.25x+40=16x+69.25
               3.25x=29.25
                      x=9
9 silver book, 9 gold book.
(3) y=19.25x+40=19.25*9+40=213.25 dollars
both companies' total cost are 213.25 dollars.