Answer:
4
Explanation:
You want the 8th term of the geometric sequence 512, 256, 128, ....
Explicit formula
The formula for the n-th term of a geometric sequence is ...
an = a1×r^(n-1)
where a1 is the first term (512), and r is the common ratio (1/2).
Then the 8th term is ...
a8 = 512(1/2)^(8-1) = 512/128 = 4
The eighth term of the sequence is 4.