求y=2x+1-2x(-4≤x≤12)的最大值和最小值．
题型：解答题
问题：
求y=2x+
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题型：解答题
假定英语课上老师要求同桌之间交换修改作文，请你修改你同学写的以下作文。文中共有10处语言错误，每句中最多有两处。错误涉及一个单词的增加、删除或修改。
增加：在缺词处加一个漏字符号（
）,并在其下面写出该加的词。
删除：把多余的词用斜线（\）划掉。
修改：在错的词下划一横线，并在该词下面写出修改后的词。
注意：1. 每处错误及其修改均仅限一词；
2．只允许修改10处，多者（从第11处起）不计分。
We'll never forget the day which my classmates and I paid a visit to a chemistry factory last week. It was a larger one with nearly 2,000 workers. It looked a garden and we could see colorful flowers, grasses and trees everywhere. We also visited some workshops and saw workers worked very hard. We talked with them and learned a lot. We understood them farther. On the way home we felt tiring. We all thought that we have a very good day. We really hoped that we could get more chances of leave the school and learn social experience.