1, when the commodity price is 12 yuan/piece, C=8 1+3Q= 12Q, thus breaking the book, and calculating Q=9, that is, at least 9 pieces can be sold to break the book.

2. Total price of 10 items sold =10x12 =120 yuan; Cost price c = 81+3x10 =11; So the profit from selling 10 items =120-11= 9 yuan.

3. If the price of goods is 2 yuan, it is impossible to calculate the cost C=8 1+3Q=2Q and deduce that q is negative. So the commodity price should not be 2 yuan/piece.