Question: I want to reduce the extra space between the first line of an answer and the start of minipage.
This is what I have done so far:
\documentclass[12pt, letterpaper]{article}
\usepackage[a4paper,top=1 in,bottom=1 in,left=0.7 in,right=0.7 in]{geometry}
\usepackage[utf8]{inputenc}
\usepackage[misc]{ifsym}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{mathtools}
\usepackage{amssymb}
\usepackage{forest}
\usepackage{tikz}
\usetikzlibrary{intersections}
\makeatother
\usepackage[parfill]{parskip}
\setlength{\parskip}{1ex}
\begin{document}
\textbf{Answer:}~Let the points are $A\,\left(x_1 , x_2\right)$, $B\,\left(y_1 , y_2\right)$ and $C\,\left(z_1 , z_2\right)$.
\begin{minipage}[b]{.5\textwidth}
\begin{flalign*}
\rightarrow AB^2&=&\\
&=&\\
\therefore\;AB&=&
\end{flalign*}
\end{minipage}%
\begin{minipage}[b]{0.5\textwidth}
\begin{flalign*}
\rightarrow BC^2&=&\\
&=&\\
\therefore\;BC&=&
\end{flalign*}
\end{minipage}
\end{document}
