\documentclass{article}
\usepackage{amsmath}

\begin{document}

\[
 \left( \begin{array}{c}
 Y \\ C_r \\ C_b
 \end{array} \right)
 =
 \left( \begin{array}{ccc}
  0.257 & 0.504 & 0.098 \\
  0.439 & 0.368 & -0.071 \\
  -0.148 & -0.291 & 0.439 \\
 \end{array} \right)
  \left( \begin{array}{c}
 R \\ G \\ B
 \end{array} \right)
\]


\end{document}