\documentclass{article} \usepackage[margin=1in]{geometry} \usepackage{amsfonts} \usepackage{amsmath} \usepackage{amsthm} \usepackage{parskip} \usepackage{amssymb} \usepackage[english]{babel} \newcommand{\R}{\mathbb{R}} \newcommand{\Z}{\mathbb{Z}} \newcommand{\N}{\mathbb{N}} \newcommand{\Q}{\mathbb{Q}} \newcommand{\C}{\mathbb{C}} \renewcommand{\P}{\mathbb{P}} \newcommand{\half}{\frac{1}{2}} \begin{document} \textit{Recreate the following expression in inline mode:} $$\left(\frac{x^3}{3(x+1)^2}\right)^{\frac{1}{n}}$$ \textit{Recreate the following proof by using align:} The solution of $ax^2+bx+c=0$ where $a\neq 0$ is \begin{align} \frac{-b\pm \sqrt{d}}{2a}\text{ where }d=b^2-4ac \end{align} \begin{proof} We see that the equation is equivalent to \begin{align} ax^2+bx&=-c \intertext{Or equivalently} -\frac{c}{a}=x^2+\frac{b}{a}x&=x^2+2\frac{b}{2a}x \intertext{By adding $\left(\frac{b}{2a})\right)^2$ to both sides we get} \left(\frac{b}{2a}\right)^2-\frac{c}{a}&=x^2+2\frac{b}{2a}+\left(\frac{b}{2a}\right)^2\\ &=\left(x+\frac{b}{2a}\right)^2 \intertext{By multiplying $4a^2$ to bot sides we get} b^2-4ac&=(2ax+b)^2 \intertext{So} \pm \sqrt{b^2-4ac}&=2ax+b \intertext{And therefore} \frac{-b \pm \sqrt{b^2-4ac}}{2a}&=x \end{align} \end{proof} \end{document}