This is a geometric sequence with a common ratio of -1/3 and an initial term of -324. Any geometric sequence can be expressed as: a(n)=ar^(n-1), in this case a=-324 and r=-1/3 so a(n)=-324(-1/3)^(n-1) so the 5th term will be a(5)=-324(-1/3)^4 a(5)=-324/81 a(5)= -4
