Ramon’s teacher wrote the following table on the board She then asked the class to write a rule for the nth term of the geometric sequence represented on the table, using the format

an=a(r)^n-1

Select the values for a and r that Ramon should use in order to correctly write the rule for the nth term.
an= ___(___)^n-1
—> number choices -3, -1/3, 1/3, 3, 9, 27, 81.
the number choices go inside the blanks.

please only respond if you know the answer :)