The nth term of a sequences of v1,v2,v3 is given by Vn=6 2^n
(1):show that for all value of n>1
Vn1=2(Vn-3)??
(2): obtain and simplify the sum of the first n term of the sequence??
I cannot parse your syntax for (1)
If Vn = 6*2^n, then clearly this is just a geometric sequence, where
a = 12
r = 2
Finding its sum is now easy, right?