Determine the 8th term in the geometric sequence whose first term is -10 and whose common ratio is 2

1 answer:

8 0

$\bf n^{th}\textit{ term of a geometric sequence}
\\\\
a_n=a_1\cdot r^{n-1}\qquad 
\begin{cases}
n=n^{th}\ term\\
a_1=\textit{first term's value}\\
r=\textit{common ratio}\\
----------\\
a_1=-10\\
r=2\\
n=8
\end{cases}
\\\\\\
a_8=-10\cdot 2^{8-1}\implies a_8=-10\cdot 2^7
\\\\\\
a_8=-10\cdot 128\implies a_8=-1280$

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