What is the 9th term of the geometric sequence 4, -20, 100, ...
First term, a = 4
common ratio, r = –20 / 4 = –5
..... ..... ..... ..... = 100 / –20 = –5
9th term = 4 ( –5 ) ^ ( 9 - 1 )
..... ...... = 4 ( –5 ) ^ 8
..... ...... = 4 ( 390,625 )
..... ...... = 1,562,500
