\documentclass[12pt]{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath,amsfonts,amssymb,amsthm}
\usepackage[margin=1.5in]{geometry}

\newtheorem{problem}{Problem}

\newtheorem{solution}{Solution}

\title{First Assignment}
\author{Pierre de Fermat\\
  Math 1\\
  Dartmouth College\\
  }
\date{\today}


\begin{document}
\maketitle
\begin{problem}
Show that for $n\geq 3$ there are no positive integer solutions to \begin{equation}
x^n+y^n=z^n.\end{equation} 
\end{problem}

\begin{solution}
Not enough space in the margins. \qed
\end{solution}

\end{document}