Which formula can be used to find the ninth term of a geometric sequence where the first term is 8 and the common ratio is -3

For a geometric sequence with a first term of "a" and a common ratio of "r", the n-th term is
.. an = a*r^(n-1)

For this problem, you have a = 8, r = -3, and n = 9. Filling these values into the formula gives
.. a9 = 8*(-3)^(9-1)
.. a9 = 8*(-3)^8


a9 = 52,488

So confused right here i need it to be more clearer