Given:
The geometric sequence is:

1 -4
2 20
3 -100
To find:
The explicit formula and list any restrictions to the domain.
Solution:
The explicit formula of a geometric sequence is:
...(i)
Where, a is the first term, r is the common ratio and
.
In the given sequence the first term is -4 and the second term is 20, so the common ratio is:



Putting
in (i), we get
where 
Therefore, the correct option is B.
Answer:
B
Step-by-step explanation:
Total segment bought=190+27=217 segments
Total length of the whole anchor=217*9/2=1953/2=976 1/2 meters
I answer is B your welcome.
This is asking you to solve the equation ...
... 27 = 3^x
You can use logarithms to find
... log(27) = x·log(3)
... log(27)/log(3) = x = 1.43136376.../0.47712125...
... x = 3
Or, you can use your knowledge of small cubes and match exponents.
... 3^3 = 3^x
... 3 = x
The answer is 2:1 because at first your ratio would be 18:9 but if you divide that by 9 (for simplifying purposes) than its 2:1