∞∞∞[latex] \left[\begin{array}{ccc}123\\456\\789\end{array}\right] \left[\begin{array}{ccc}123\\456\\789\end{array}\right] x^{123} [/latex]

∞∞∞[latex] \left[\begin{array}{ccc}1&2&3\\4&5&6\\7&8&9\end{array}\right] \left[\begin{array}{ccc}1&2&3\\4&5&6\\7&8&9\end{array}\right] x^{123} [/latex]