Answer:
-9447840
Explanation:
You want the first term of a geometric sequence whose 11th term is -160 and whose common ratio is -1/3.
N-th term
The n-th term of a geometric sequence is ...
an = a1·r^(n-1)
where a1 is the first term and r is the common ratio.
Using the given values, we have ...
-160 = a1·(-1/3)^(11 -1)
a1 = (-160)·(-3)^10 = -9447840
The first term is -9447840.