A

17. Let {a_n} be a geometric sequence for which a₃ = 8 and a₆ = 128. Then a₁ =

A. 1/2	B. 1	C. 2^1/3
D. 4^1/3	E. 2

Solution: The answer is C

Since {a_n} is a geometric sequence, we have the following relationships,

Thus, solving for r will enable us to find a, and hence a₁.

Solve for r:

Find a:

Hence, a₁ = 2^1/3