This is my whole tex file:
\documentclass[12pt]{book}
\usepackage{amsmath,polynom,amssymb,venndiagram,mathtools}
\begin{document}
\pagestyle{empty}
\title{Diophantine Equations}
\author{Sew Qian Hong}
\date{13 June 2018}
\maketitle
\tableofcontents
\chapter{Factorization}
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
\chapter{Linear Diophantine Equations}
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.
Diophantine equations are polynomial equations with integral coefficients for which integral solutions are required.

\end{document}. And perhaps have a look at the geometry package.... or just add\usepackage[margin=3cm]{geometry}, say. And as for "why" this happens: books, i.e. these curious things people were using in the previous Millenium, typically distinguish between even and odd sides, that is there is an inner edge and an outer edge ... – Jun 13 '18 at 04:10> texdoc memdesign). – Peter Wilson Jun 13 '18 at 18:18onesidein the document class:\documentclass[oneside]{abntex2}– Daniel Terra Gomes Jan 15 '24 at 17:50