Answer:
Step-by-step explanation:
The sequence -2, -6, -18, -54, ... is a geometric one, since each new term is 3 times the previous term. In other words, 3 is the common ratio.
The general formula for a geometric sequence is
a(n) = a(1)*(r)^(n - 1), where r is the common ratio and a(1) is the first term.
Here,
a(n) = -2*(3)^(n-1)
