Uncle lee harvests 1000 pounds of wheat and he wants to use either small bags or large bags to pack the wheat. If he uses 10 small bags and 7 large bags, there will be some wheat left unpacked; if he uses 7 small bags and 10 large bags, one of the bags will not be fully occupied. What is the system of inequalities representing the capacity of each type of bags? Let x=small bags and y=large bags