\[b_{6} \cdot b_{22} = 81\]
\[b_{1} \cdot q^{5} \cdot b_{1} \cdot q^{21} = 81\]
\[b_{1}^{2} \cdot q^{26} = 81\]
\[\left( b_{1} \cdot q^{13} \right)^{2} = 81\]
\[b_{1} \cdot q^{13} = 9 \Longrightarrow b_{14} = 9\ \ или\ \ \]
\[b_{1} \cdot q^{13} = - 9 \Longrightarrow b_{14} = - 9.\]
\[Ответ:9\ \ или\ \ ( - 9)\text{.\ }\]