\documentclass{article}
\usepackage{amsmath}
\begin{document}

\begin{equation}
  \left[
    \begin{matrix}
      R_{1 x}\\
      R_{1 y}\\
      F_{2 x}\\
      F_{2 y}\\
      R_{3 x}\\
      R_{3 y}\\
      R_{4 x}\\
      R_{4 y}
    \end{matrix}
  \right]
  =
  \left[
    \begin{matrix}
      \frac{A_{1} E_{1}}{L_{1}} & 0 & - \frac{A_{1} E_{1}}{L_{1}} & 0 & 0 & 0 & 0 & 0\\
      0 & 0 & 0 & 0 & 0 & 0 & 0 & 0\\
      - \frac{A_{1} E_{1}}{L_{1}} & 0 & \frac{A_{1} E_{1}}{L_{1}} + \frac{A_{3} E_{3}}{5 L_{3}} & - \frac{2 A_{3} E_{3}}{5 L_{3}} & 0 & 0 & - \frac{A_{3} E_{3}}{5 L_{3}} & \frac{2 A_{3} E_{3}}{5 L_{3}}\\
      0 & 0 & - \frac{2 A_{3} E_{3}}{5 L_{3}} & \frac{A_{2} E_{2}}{L_{2}} + \frac{4 A_{3} E_{3}}{5 L_{3}} & 0 & - \frac{A_{2} E_{2}}{L_{2}} & \frac{2 A_{3} E_{3}}{5 L_{3}} & - \frac{4 A_{3} E_{3}}{5 L_{3}}\\
      0 & 0 & 0 & 0 & 0 & 0 & 0 & 0\\
      0 & 0 & 0 & - \frac{A_{2} E_{2}}{L_{2}} & 0 & \frac{A_{2} E_{2}}{L_{2}} & 0 & 0\\
      0 & 0 & - \frac{A_{3} E_{3}}{5 L_{3}} & \frac{2 A_{3} E_{3}}{5 L_{3}} & 0 & 0 & \frac{A_{3} E_{3}}{5 L_{3}} & - \frac{2 A_{3} E_{3}}{5 L_{3}}\\
      0 & 0 & \frac{2 A_{3} E_{3}}{5 L_{3}} & - \frac{4 A_{3} E_{3}}{5 L_{3}} & 0 & 0 & - \frac{2 A_{3} E_{3}}{5 L_{3}} & \frac{4 A_{3} E_{3}}{5 L_{3}}
    \end{matrix}
  \right]
  \left[
    \begin{matrix}
      0\\
      0\\
      u_{2 x}\\
      u_{2 y}\\
      0\\
      0\\
      0\\
      0
    \end{matrix}
  \right]
\end{equation}
\end{document}
