\documentclass[12pt]{article}
\usepackage{amssymb,amsmath,amscd,concmath,amsfonts}
\usepackage{color}
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\begin{document}
\begin{equation*}
  \begin{aligned}
    \frac{dz}{dt}&=
    \begin{bmatrix}
        -a_1- \tilde k_1 & -a_2- \tilde k_2 & -a_3- \tilde k_3 & 
	  \dots & -a_n- \tilde k_n \\
        1 & 0 & 0 & \dots & 0 \\
        0 & 1 & 0 & \dots & 0 \\
        \vdots & & \ddots & \ddots & \vdots \\
        0 & & & 1 & 0\\
    \end{bmatrix} z+
    \begin{bmatrix}
      k_r \\ 0 \\0\\ \vdots\\ 0
    \end{bmatrix} r, \\
    y &= {\color{blue} \begin{bmatrix} b_1 & b_2 & \cdots & b_n \end{bmatrix}} z.
  \end{aligned}  
\end{equation*}
\end{document}