即使启用了 allowdisplaybreaks，多列对齐环境也会被切断

Question

梅威瑟：

    \documentclass{article}
\usepackage[top=3cm,bottom=3cm,left=3.2cm,right=3.2cm,headsep=10pt,a4paper]{geometry} 
\usepackage{amsmath,amsfonts,amssymb,amsthm}
\usepackage{enumitem} 
\usepackage{multicol}
\setlength{\columnsep}{1cm} 
\setlength{\columnseprule}{1pt}
\allowdisplaybreaks

\begin{document}

\begin{multicols*}{2}

\begin{enumerate}[label=(\alph*)]
\item $\begin{aligned}[t]
2x+6&=12x-8\\
2x-12x&=-8-6\\
-10x&=-14\\
x&=\dfrac{-14}{-10}\\
&=1\dfrac{2}{5}
\end{aligned}$
\item $\begin{aligned}[t]
4x-5&=6(7)\\
&=42\\
4x&=42+5\\
&=47\\
x&=\dfrac{47}{4}\\
&=11\dfrac{3}{4}
\end{aligned}$
\item $\begin{aligned}[t]
5(6x-2)&=3(9x+1)\\
30x-10&=27x+3\\
30x-27x&=3+10\\
3x&=13\\
x&=\dfrac{13}{3}\\
&=4\dfrac{1}{3}
\end{aligned}$
\item $\begin{aligned}[t]
\dfrac{3(-2x+5)-4(8x+1)}{12}&=7\\
\dfrac{-6x+15-32x-4}{12}&=7\\
\dfrac{-38x+11}{12}&=7
\end{aligned}$\\
$\begin{aligned}[t]
-38x+11&=12(7)\\
&=84\\
-38x&=84-11\\
&=73\\
x&=\dfrac{73}{-38}\\
&=-1\dfrac{35}{38}
\end{aligned}$
\item $\begin{aligned}[t]
3&=7(x+5)\\
3&=7x+35\\
-7x&=35-3\\
&=32\\
x&=\dfrac{32}{-7}\\
&=-4\dfrac{4}{7}
\end{aligned}$
\item $\begin{aligned}[t]
4(5x+6)&=6(3x-2)\\
20x+24&=18x-12\\
20x-18x&=-12-24\\
2x&=-36\\
x&=\dfrac{-36}{2}\\
&=-18
\end{aligned}$
\end{enumerate}


\end{multicols*}

\end{document}

可以看出，尽管我添加了\allowdisplaybreaks，但页面底部的方程式被截断了。我该如何解决这个问题？

Answer 1

您需要使用显示数学结构来允许分页：

    \documentclass[,fleqn,leqno]{article}
\usepackage[top=3cm,bottom=3cm,left=3.2cm,right=3.2cm,headsep=10pt,a4paper]{geometry} 
\usepackage{amsmath,amsfonts,amssymb,amsthm}
\usepackage{enumitem} 
\usepackage{multicol}
\setlength{\columnsep}{1cm} 
\setlength{\columnseprule}{1pt}
\renewcommand\theequation{\alph{equation}}
\allowdisplaybreaks

\begin{document}

\begin{multicols*}{2}

\begin{align}
2x+6&=12x-8\\
2x-12x&=-8-6\nonumber\\
-10x&=-14\nonumber\\
x&=\dfrac{-14}{-10}\nonumber\\
&=1\dfrac{2}{5}\nonumber
\end{align}

\begin{align}
4x-5&=6(7)\\
&=42\nonumber\\
4x&=42+5\nonumber\\
&=47\nonumber\\
x&=\dfrac{47}{4}\nonumber\\
&=11\dfrac{3}{4}\nonumber
\end{align}
\begin{align}
5(6x-2)&=3(9x+1)\\
30x-10&=27x+3\nonumber\\
30x-27x&=3+10\nonumber\\
3x&=13\nonumber\\
x&=\dfrac{13}{3}\nonumber\\
&=4\dfrac{1}{3}\nonumber
\end{align}
\begin{align}
\dfrac{3(-2x+5)-4(8x+1)}{12}&=7\\
\dfrac{-6x+15-32x-4}{12}&=7\nonumber\\
\dfrac{-38x+11}{12}&=7\nonumber
\end{align}
\begin{align}
-38x+11&=12(7)\\
&=84\nonumber\\
-38x&=84-11\nonumber\\
&=73\nonumber\\
x&=\dfrac{73}{-38}\nonumber\\
&=-1\dfrac{35}{38}\nonumber
\end{align}
\begin{align}
3&=7(x+5)\\
3&=7x+35\nonumber\\
-7x&=35-3\nonumber\\
&=32\nonumber\\
x&=\dfrac{32}{-7}\nonumber\\
&=-4\dfrac{4}{7}\nonumber
\end{align}
\begin{align}
4(5x+6)&=6(3x-2)\\
20x+24&=18x-12\nonumber\\
20x-18x&=-12-24\nonumber\\
2x&=-36\nonumber\\
x&=\dfrac{-36}{2}\nonumber\\
&=-18\nonumber
\end{align}



\end{multicols*}

\end{document}

Answer 2

您不能破坏里面的方程式aligned，而且由于您有如此奇怪的要求，所以这里是一次尝试flalign*。

\documentclass{article}
\usepackage[top=3cm,bottom=3cm,left=3.2cm,right=3.2cm,headsep=10pt,a4paper]{geometry}
\usepackage{amsmath,amsfonts,amssymb,amsthm}
\usepackage{enumitem}
\usepackage{multicol}
\setlength{\columnsep}{1cm}
\setlength{\columnseprule}{1pt}
\allowdisplaybreaks

\begin{document}

\begin{multicols*}{2}

\begin{enumerate}[label=(\alph*)]
\setlength{\abovedisplayskip}{0pt}
\item \leavevmode\vspace{-\baselineskip}
 \begin{flalign*}
2x+6&=12x-8&\\
2x-12x&=-8-6&\\
-10x&=-14&\\
x&=\frac{-14}{-10}&\\
&=1\frac{2}{5}&
\end{flalign*}
\item \leavevmode\vspace{-\baselineskip}
 \begin{flalign*}
4x-5&=6(7)&\\
&=42&\\
4x&=42+5&\\
&=47&\\
x&=\dfrac{47}{4}&\\
&=11\dfrac{3}{4}&
\end{flalign*}
\item \leavevmode\vspace{-\baselineskip}
 \begin{flalign*}
5(6x-2)&=3(9x+1)&\\
30x-10&=27x+3&\\
30x-27x&=3+10&\\
3x&=13&\\
x&=\dfrac{13}{3}&\\
&=4\dfrac{1}{3}&
\end{flalign*}
\item \leavevmode\vspace{-\baselineskip}
 \begin{flalign*}
\dfrac{3(-2x+5)-4(8x+1)}{12}&=7&\\
\dfrac{-6x+15-32x-4}{12}&=7&\\
\dfrac{-38x+11}{12}&=7&
\end{flalign*}
\leavevmode\vspace{-\baselineskip}
 \begin{flalign*}
-38x+11&=12(7)&\\
&=84&\\
-38x&=84-11&\\
&=73&\\
x&=\dfrac{73}{-38}&\\
&=-1\dfrac{35}{38}&
\end{flalign*}
\item \leavevmode\vspace{-\baselineskip}
 \begin{flalign*}
3&=7(x+5)&\\
3&=7x+35&\\
-7x&=35-3&\\
&=32&\\
x&=\dfrac{32}{-7}&\\
&=-4\dfrac{4}{7}&
\end{flalign*}
\item \leavevmode\vspace{-\baselineskip}
 \begin{flalign*}
4(5x+6)&=6(3x-2)&\\
20x+24&=18x-12&\\
20x-18x&=-12-24&\\
2x&=-36&\\
x&=\dfrac{-36}{2}&\\
&=-18&
\end{flalign*}
\end{enumerate}


\end{multicols*}

\end{document}