Answer:
The explicit form is 
Step-by-step explanation:
The explicit form of a geometric sequence is given by:

where an is the nth term, a is the first term of the sequence and r is the common ratio.
In this case:
a=162
The value of the common ratio is obtained by dividing one term by the previous term.
For the first and second terms:
108/162=2/3
For the second and third terms (In order to prove that 2/3 is the common ratio)
72/108=2/3
Therefore:
r=2/3
Replacing a and r in the formula:

Answer:
b=7
Step-by-step explanation:
The interest would be $123.5
Answer:
<em>Functions:</em>
3. The chart with arrows
4. The graph
<em>Not Functions:</em>
1. (1,1), (2,2), (3,3), (1,4)
2. (1,17), (0,16), (0,15), (-2,17)
Step-by-step explanation:
Functions do not have repeating domains (x-coordinates).
Hope it helps!