Đáp án:
$\begin{array}{l}
\left\{ \begin{array}{l}
S = \frac{{{u_1}}}{{1 - q}} = 2\\
{u_1} + {u_2} + {u_3} = 9494
\end{array} \right.\\
\Rightarrow \left\{ \begin{array}{l}
{u_1} = 2 - 2q\\
{u_1}\left( {1 + q + {q^2}} \right) = 9494
\end{array} \right.\\
\Rightarrow 2.\left( {1 - q} \right)\left( {1 + q + {q^2}} \right) = 9494\\
\Rightarrow 1 - {q^3} = 4747\\
\Rightarrow {q^3} = - 4746\\
\Rightarrow q = - \sqrt[3]{{4746}}\\
\Rightarrow {u_1} = 2 - 2q = 2 + 2.\sqrt[3]{{4746}}
\end{array}$
