Find the indicated term of the sequence.
-The fourth term of the geometric sequence whose first term is 9 and whose common ratio is -2
A) 144
B) -8
C) 72
D) -72

Question

Quizplus · Accepted Answer

The fourth term of a geometric sequence is found using the formula $a_n = a_1 \cdot r^{(n-1)}$, where $a_n$ is the nth term, $a_1$ is the first term, $r$ is the common ratio, and $n$ is the term number. For the fourth term, $n=4$, $a_1=9$, and $r=-2$, so $a_4 = 9 \cdot (-2)^{4-1} = 9 \cdot (-2)^3 = 9 \cdot (-8) = -72$.

Find the Indicated Term of the Sequence