将对齐环境的第一行与其前一行文本的基线对齐

Question

这可能是排版不好，但我的资源有限，我既想又需要节省纸张。这不是要出版的东西，所以数学论文的标准不必适用。这是高中数学课的。

我想创建类似下面的东西：

我可以通过一些小技巧来实现

\documentclass{article}
\usepackage[textwidth=4in]{geometry}
\setlength\parskip{2ex}
\setlength\parindent{0pt}
\usepackage{amsmath}
\newcounter{ae@problem}
\newcommand\problem{\stepcounter{ae@problem}\textbf{P\arabic{ae@problem}}\hspace*{1em}}
\begin{document}

There is one mistake in each of the problems.  Identify the mistake by
circling it.  Then correct the work.

\problem 
\begin{minipage}[t]{2.5in}
\vspace{-\dimexpr\abovedisplayskip+\abovedisplayshortskip+\baselineskip}
\begin{align*}
  \text{For } h(x) &= x^{2}+2x+4 \\
  h(-3) &= -3^{2}+2(-3)+4 = -9-6+4 \\&= -15 + 4 = -11
\end{align*}
\end{minipage}

\end{document}

是否有更简单的方法或更适合此目的的对齐环境？

我希望文本的第一行按以下方式排列：

\documentclass{article}
\usepackage[textwidth=4in]{geometry}
\setlength\parskip{2ex}
\setlength\parindent{0pt}
\usepackage{amsmath}
\newcounter{ae@problem}
\newcommand\problem{\stepcounter{ae@problem}\textbf{P\arabic{ae@problem}}\hspace*{1em}}
\begin{document}

There is one mistake in each of the problems.  Identify the mistake by
circling it.  Then correct the work.

\problem For $h(x) = x^{2}+2x+4$.
\begin{align*}
  h(-3) &= -3^{2}+2(-3)+4 = -9-6+4 \\&= -15 + 4 = -11
\end{align*}

\end{document}

但是我不喜欢对齐环境的第一个等号与第一行上的函数呈现不一致。

Answer 1

\documentclass{article}
\usepackage[textwidth=4in]{geometry}
\setlength\parskip{2ex}
\setlength\parindent{0pt}
\usepackage{amsmath}
\newcounter{ae@problem}
\newcommand\problem{\stepcounter{ae@problem}\textbf{P\arabic{ae@problem}}\hspace*{1em}}
\begin{document}

There is one mistake in each of the problems.  Identify the mistake by
circling it.  Then correct the work.
\begin{flalign*}
\textrm{\problem For } h(x) &= x^{2}+2x+4 &\\[\parskip]
  h(-3) &= -3^{2}+2(-3)+4 = -9-6+4 &\\
  &= -15 + 4 = -11 &
\end{flalign*}

\end{document}

当然，如果你把它放在flaign段落开头，空间就会太大。有几种方法可以解决这个问题，但没有一种是理想的。

Answer 2

下面是另一个选项，它使用某种形式\tag来放置问题：

\documentclass{article}
\usepackage[textwidth=4in]{geometry}% Just for this example
\usepackage{amsmath}

\makeatletter% http://tex.stackexchange.com/a/193538/5764
\newcommand{\leqnomode}{\tagsleft@true}
\newcommand{\reqnomode}{\tagsleft@false}
\makeatother

\newcounter{problemcnt}
\newenvironment{problem}
  {\leqnomode
   \refstepcounter{problemcnt}%
   \csname align*\endcsname% http://tex.stackexchange.com/a/13994/5764
     \tag*{\bfseries P\theproblemcnt}
  }{%
    \csname endalign*\endcsname
    \reqnomode}
\begin{document}

There is one mistake in each of the problems.  Identify the mistake by
circling it. Then correct the work.
\begin{problem}
  \text{For } h(x) &= x^{2}+2x+4 \\
             h(-3) &= -3^{2}+2(-3)+4 = -9-6+4 \\
                   &= -15 + 4 = -11
\end{problem}

\end{document}