Answer:
635/64
Step-by-step explanation:
General formula of geometric sequence:
[tex]u_{n} = ar^{n - 1} [/tex]
Un = nth term
a = first term
If we plug in the what we are given into the general formula for the 7th term, we can solve for the first term:
[tex]u_{7} \: (or \: s_{7}) = a(2)^{7 - 1} = 635 \\ \\ a(2)^{6} = 635 \\ \\ 64a = 635 \\ \\ a = \frac{635}{64} [/tex]
