Question 1086787
The n-th term of a geometric sequence is a_n = a*r^(n-1) where r is the common ratio and a is the 1st term.
In this case, r = 2, and the 1st term is 6.
Thus a_n = 768 = 6*2^(n-1)
768/6 = 128 = 2^(n-1)
Since 2^7 = 128 -> n - 1 = 7, or n = 8
786 is the 8th term.