a5/a8=-27
a5/a5q^3=-27
1/q^3=-27
q^3=-1/27
q=-1/3
(a3+a5+a7)/(a4+a6+a8)
=(a3+a5+a7)/(a3q+a5q+a7q)
=(a3+a5+a7)/[q(a3+a5+a7)]
=1/q
=1/(-/3)
=-3
a5/a8=-27
a5/a5q^3=-27
1/q^3=-27
q^3=-1/27
q=-1/3
(a3+a5+a7)/(a4+a6+a8)
=(a3+a5+a7)/(a3q+a5q+a7q)
=(a3+a5+a7)/[q(a3+a5+a7)]
=1/q
=1/(-/3)
=-3