Split an equation of matrix

Question

Could anyone guide me on how to split an equation of matrix?

I have tried this code but the functions of delimiter '&' are intercepted (functions of split and matrix)

\begin{equation}
\begin{split}
\[
a&=\begin{bmatrix}
1&2&3&4\\
5&6&7&8\\
\end{bmatrix}&=66
\]
\end{split}
\end{equation}

Thank you

Answer 1

Welcome to TeX.SE!

• please always provide MWE (Minimal Working Example)
• your code fragment is quite strange, correct MWE is:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
    \begin{equation}
\begin{split}
a &=\begin{bmatrix}
1&2&3&4\
5&6&7&8\
\end{bmatrix}   \  % <----
&=66
\end{split}
    \end{equation}
\end{document}