\[\boxed{\mathbf{817\ (817).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[2)\ 4,\ 8,\ 16,\ 32,\ \ \]
\[b_{1} = 4;\ \ q = 2;\]
\[4)\ 81,\ 27,\ 9,\ 3,\ \ \]
\[b_{1} = 81;\ \ q = \frac{1}{3};\]
\[5)\ 2;\ - 2;2;\ - 2,\ \ \]
\[b_{1} = 2;\ \ q = - 1;\]
\[6) - \frac{1}{4},\ \ \ \frac{1}{2},\ - 1,\ 2,\ \ \]
\[b_{1} = - \frac{1}{4};\ \ q = - 2;\]
\[7) - 9;\ - 9;\ - 9;\ - 9,\ \ \]
\[b_{1} = - 9;\ \ q = 1;\]
\[9)\ \sqrt{2};2;2\sqrt{2};4,\ \ \]
\[b_{1} = \sqrt{2};\ \ q = \sqrt{2}.\]