TeX джерело:

\normalsize{\;AX\;=\;\left( \begin{array}{c}a_{11}x_1\,+\,a_{12}x_2\,+\dots+\,a_{1n}x_n\\a_{21}x_1\,+\,a_{22}x_2\,+\dots+\,a_{2n}x_n\\ \dots\;\dots\;\dots\;\dots\;\dots\;\dots \\a_{m1}x_1+a_{m2}x_2+\dots+a_{mn}x_n \end{array}\right)}