已知等比数列{an}中,a1+a3=10,a4+a6+5/4,Sn是数列{an}的前n项和,求a5和S6

a4/a1=q³
a6/a3=q³
则(a4+a6)/(a1+a3)=1/8=q³
q=1/2
a1+a3=a1+a1q²=5/4a1=10
a1=8
所以a5=a1q^4=1/2
S6=a1(1-q^6)/(1-q)=63/4