(2x+13x)n的展开式中各项系数之和为729,则该展开式中x2的系数为___ 发布时间:2017-05-16 10:45 │ 来源:www.tikuol.com 题型:填空题 问题: (2x+13x)n的展开式中各项系数之和为729,则该展开式中x2的系数为______.
题型:填空题 用be动词的适当形式填空。(5分)小题1:What ________ (be) this ?小题2:How ________ (be) you, Kate?小题3:Her phone number ________ (be) 92676929.小题4:Who ________ (be) I ?小题5:Tom and I ________ (be) from England. 查看答案