Question

What is the 9th term of the geometric sequence where a1 = –5 and a6 = –5,120?

Answer 1

d = (-5120 + 5)/5 wince we are looking for 4 arithmetic means between a1 and a6

Answer 2

an = a1 + d(n-1) is the general formula to find any nth term in an arith sequence

Answer 3

a9 = a1 + d(8)

a9 = -5 + (-5120+5)8/5

Answer 4

@amistre64 the original question is asking for a geometric sequence, just fyi

Answer 5

use this formula

Answer 6

you will need a common ratio