答案1
我会这样写:
\documentclass{article}
\usepackage{witharrows}
\usepackage{amstext} % for \text
\begin{document}
\begin{DispWithArrows*}[wrap-lines]
x^2 = 25
& \Longleftrightarrow x^2-25 = 0 \\
& \Longleftrightarrow (x-5)(x+5) = 0
\Arrow{a product equals zero iff a factor equals zero} \\
& \Longleftrightarrow x=5 \text{ or } x=-5
\end{DispWithArrows*}
\end{document}