网址:http://m.1010jiajiao.com/timu_id_4064163[举报]
等比数列{an}中,a2=9,a5=243,则{an}的前4项和为( ).
A.81 B.120 C.168 D.192
等比数列{an}中,a2=9,a5=243,则{an}的前4项和为( )
A. 81 B. 120 C. 168 D. 192