\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
MX_i =
\left[
\begin{Bmatrix} r_i \\ g_i \\ b_i \end{Bmatrix}
+
\begin{Bmatrix}
0.412391 & 0.357584 & 0.180481 \\
0.212639 & 0.715169 & 0.072192 \\
0.019331 & 0.119195 & 0.950532
\end{Bmatrix}
\right]
\]
\end{document}