已知等差数列{an}、{bn}的前n项和分别为Sn、Tn,若SnTn=3n+15 发布时间:2017-04-27 07:16 │ 来源:www.tikuol.com 题型:填空题 问题: 已知等差数列{an}、{bn}的前n项和分别为Sn、Tn,若SnTn=3n+155n+7,则a9b9=______.
题型:填空题 选出不同类的单词。( ) 1. A. bus ( ) 2. A. white( ) 3. A. peach( ) 4. A. red ( ) 5. A. brownB. car B. eraser B. pear B. eye B. green C. dog C. pink C. orange C. black C. TV D. bikeD. blackD. pencilD. orangeD. yellow 查看答案