已知SN是等差数列,S6=36,SN=324,S(N-6)=144,则N=?

已知SN是等差数列,S6=36,SN=324,S(N-6)=144,则N=? 已知等差数列前n项和为Sn,S6/S3=3 求S9除S6 设Sn是等差数列{an}的前n项和,已知S6=36,Sn=324,Sn-6=144（n>6),则n等于? 已知Sn是等差数列An的前n项和,6,已知S6=36,Sn=360,Sn-6=21,求项数n 求详细解题过程,谢谢,急求!已知Sn是等差数列An的前n项和,已知S6=36，Sn=360，Sn-6=216，求项数n 不好意思写错了，真的不好意思 设Sn是等差数列{an}的前n项和好,已知S6=36,Sn=324,S(n-6)=144,n>6,则n= 设Sn是等差数列an的前n项和,若S3/S6=1/3,则S6/S7=? Sn是等差数列an前n项和,若S3/S6=1/3,则S6/S12=? 设Sn是等差数列(An)的前n项和,若S3/S6=1/3,求S6/S12=? 设Sn是等差数列{An}的前n项和,若S3/S6=1/3,则S6/S12=? 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,若S3/S6=1/3,则S6/S12=? 设Sn是等差数列An的前n项和,若S3/S6=1/3,则S6/S12等于 设Sn是等差数列{an}的前n项和,若S3/S6=1/3,求S6/S12 sn是等差数列｛an}前n项和,若s3/s6=1/3,求s6/s12 1.设Sn是等差数列【An]的前n项和,若S3/S6=1/3,求S6/S12 等差数列{an}的前n项和记为Sn,已知S6=36,Sn=324,Sn-6=144(n>6),则n等于? 等差数列(an)的前n项和sn,若s6：s3=3,求s9：s6 Sn是等差数列前n项和,已知S6=36,Sn=324,Sn-6=144,则n的值为?这题运算量忒大,有没有简便的?没有把步骤详细写出来.忘了