把m 个练习本分给n 个学生，如果每人分3本，那么余80本；如果每人分5本，那么最后一个同学有练习本但不足5本，n的值为____.

下图为植物光合作用强度随光照强度变化的坐标图，下列叙述中不正确的是(　　)。

①y= $\frac{-5}{2x-1}$ ②y= $\sqrt{2x-1}$ ．

    Good morning, everyone! Welcome to Cool Food Store. Christmas Day is next Sunday. Our 1is on sale for Christmas.2and have a look. We have hamburgers3 only 7 dollars. Do you like snacks（零食）? We 4 all kinds（种类）of snacks. You can also buy vegetables at our store—potatoes, 5 They are all 6. Our drinks（饮料）are all at good 7 Juice is 2 dollars. Coke is 3 dollars. How much is our milk? Oh, it's only 1 dollar. Do you need fruit? Come to our store. We have many fruits, like（例如）oranges, pears and strawberries. Our store is open（营业的）8 9:00 am to 9:00 pm every day. 9 want it, we have it. Come to our store to buy some of your favorite food. Then you can have a10dinner with your family on Christmas Day.