答案1
您的问题不太清楚,但这是按第一个=
符号对齐的方程组。
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
\left\{ \begin{aligned}
\frac{\partial L}{\partial W_N}&=0 \rightarrow W_N=\sum_{k=1}^{L'}\alpha_k^{''}y_k^{}\varphi_2^{}(x_k^{}N)\\
\frac{\partial L}{\partial W_b}&=0 \rightarrow W_N=\sum_{k=1}^{L'}\alpha_k^{''}y_k^{}=0\\
\frac{\partial L}{\partial W_{e_k}}&=0 \rightarrow \gamma e_k^{}k=1,2,\dots,L'\\
\frac{\partial L}{\partial W_{\alpha_k^{''}}}&=0 \rightarrow k\biggl[\binom{W_M}{W_N}^T\binom{\varphi_1^{}{x_{KM}^{}}}{\varphi_2^{}{x_{KN}^{}}}+b\biggr]-1+e_k^{}=0\\
\end{aligned} \right.
\end{equation*}
\end{document}