Question

The first 3 terms of the GP are x-2, x-1 and x+7 find

(A) the value of x
(B) the common ratio
(C)S6

Answer 1

(x-1)^2 = (x-2)(x+7)

x = 15/7
r = 8, a = 1/7
S6 = (1/7)(8^6-1)/(8-1)