已知等差數列{an}前n項和為Sn,且a3+a8=13,S7=35,則a7=______.

已知等差數列{an}前n項和為Sn,且a3+a8=13,S7=35,則a7=______.

∵等差數列{an}前n項和為Sn,且a3+a8=13,S7=35,∴2a1 ;+9d=137a1+21d=35,解得a1=2,d=1,∴a7=2+6×1=8.故答案為:8.