@debbie Why do we multiply by (2/3)^9 instead of (2/3)^8?
I thought that the first term is 1 so we have to subtract 1 from n. does 1 not count as a term?

@energizedpanda Yeah, you're absolutely right! It needs to specify that 1 is the 0th term in order for (3/2)^9 to be correct. I'll go ahead and report that now!