The 2nd, 6th and 8th terms of an Arithmetic progression are three successive terms of a Geometric.P.Find the common ratio of G.P and obtain an expression for nth term of the G.P. (question)

my first step is to find the common ratio, and i get r=2.....but i cant obtain others constant to find the expression...anyone know how to find that?

Sent from my Lenovo A5000 using Tapatalk