已知等差数列Sn中,S3=9,S9=3,S12=?

已知等差数列Sn中,S3=9,S9=3,S12=? 已知等差数列前n项和为Sn,S6/S3=3 求S9除S6 已知Sn为等差数列an前n项和,若S9/S3=3,则a9/a3=? 等差数列(an)的前n项和sn,若s6：s3=3,求s9：s6 在等差数列{an}中S3=9,S9=3,则S12=? 已知等差数列﹛an﹜前几项和Sn,S3=6 ,S7+S8+S9=170,求S30 已知等差数列｛an｝中S3＝9,S9＝3,则S12＝ 已知等差数列{an}的前n项和为sn,若s6/s3=3,则s12/s9=?（求详细答案） 已知等比数列{an}的公比为q,前n项和为Sn,且S3,S9,S6成等差数列,则q^3= Sn是等差数列前N项和,且S5/S3=9/5 求S9/S5SORRY.说错了.是Sn是等差数列前N项和,且S5/S3=5/9 求S9/S5 设Sn是等差数列an的前n项和,若S5/S3=5/9,则S9/S5= 等差数列an的前n项和为sn若s6/S3=3,则s9/S6=? 设等差数列{an}的前n项和为Sn,若S6/S3=3,则S9/S6=? 设Sn是等差数列的前n项和,S3:S6=1:3,则S6:S9= 设Sn是等差数列an的前n项和,s6/s12=3/10,则s3/s9=¿ 等差数列中S6比S3=3则S12比S9=? Sn是等差数列前N项和,S3=S9,那么S5=S几 等差数列的前n项和为Sn,若S3=S6,则S9=?