Splitting a long equation please help

Question

I am using this:

\documentclass[12pt,letter paper] {article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english]{babel}
\usepackage{graphicx}
\usepackage[capposition=top]{floatrow}
\usepackage[a4paper,left=25mm,top=25mm,top=25mm,bottom=25mm]{geometry}
\usepackage{amsmath}
\begin{document} 


\begin{align*}
    {LogTAXREV}_{it} = {\alpha_{0}}+{\beta_{1}LogGDPPC_{it}}
    +{\beta_{2}LogTRADE_{it}}+{\beta_{3}LogRESOURCE_{it}}
   +{\beta_{4}LogAGRIC_{it}}+{\beta_{5}LogSERVICE_{it}}
   +{\beta_{6}LogAGE_{it}}+{\beta_{7}LogPOP_{it}}
   +{\beta_{8}LogEDUC_{it}}+{\beta_{9}LogGINI_{it}}
\end{align*}

\end{document}

I get this error: Argument of @fileswith@pti@ns has an extra } on the amsmath usepackage and my equation does not split.

Answer 1

Line 1: letter paper should be letterpaper, but you can omit it altogether, since you're declaring a4paper later.

Line 2: with a recent release of LaTeX available, this can be omitted.

Line 7: you're missing a trailing {geometry}, which is the cause of the first error you get.

In the main part, all those \emph declarations are wrong. And TeX won't split the long equation for you.

\documentclass[12pt] {article}
%\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[english]{babel}
\usepackage{graphicx}
\usepackage[capposition=top]{floatrow}
\usepackage[a4paper,left=25mm,top=25mm,top=25mm,bottom=25mm]{geometry}
\usepackage{amsmath}

\begin{document} 


\begin{align*}
  \mathit{LogTAXREV}_{\mathrm{it}} = \alpha_{0}
  &+\beta_{1}\mathit{LogGDPPC}_{\mathrm{it}}
   +\beta_{2}\mathit{LogTRADE}_{\mathrm{it}}
  \\
  &+\beta_{3}\mathit{LogRESOURCE}_{\mathrm{it}}
   +\beta_{4}\mathit{LogAGRIC}_{\mathrm{it}}
  \\
  &+\beta_{5}\mathit{LogSERVICE}_{\mathrm{it}}
   +\beta_{6}\mathit{LogAGE}_{\mathrm{it}}
  \\
  &+\beta_{7}\mathit{LogPOP}_{\mathrm{it}}
   +\beta_{8}\mathit{LogEDUC}_{\mathrm{it}}
  \\
  &+\beta_{9}\mathit{LogGINI}_{\mathrm{it}}
\end{align*}

\end{document}