Question

Find the 15th term of the sequence: -3, 6, -12, 24
A. 123
B. -49,152
C. -123
D. 49,152

Answer 1

Hi, the sequence is being multiplied by -2.

Can you work it out using this information?

Answer 2

\(\bf -3, 6, -12, 24\qquad \textit{common ratio}=-2\\ \quad \\
\large a_n=a_1\cdot r^{n-1}\implies a_{{\color{red}{ 15}}}=a_1\cdot r^{{\color{red}{ 15}}-1}\\ \quad \\
a_1=\textit{1st term}\\
r=\textit{common ratio}\)