I have this array:
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath, amsfonts}
\usepackage[thicklines]{cancel}
\title{shortenedExample}
\author{CATboardBETA}
\date{February 2022}
\DeclareMathSymbol{\shortminus}{\mathbin}{AMSa}{"39}
\begin{document}
\Huge
\begin{equation}
\begin{array}{rcccccccc}
& 45 & = & \overbrace{3x}^{\text{small}} & + & \overbrace{5y}^{\text{large}} \\[.4em]
& 10 & = & x & + & y \\
\times & \shortminus3 &&\shortminus3&&\shortminus3 \\
\hline
& \shortminus30 & = & \shortminus3x & + & \shortminus3y \\[1em]
& 45 & = & 3x & + & 5y \\
+ & \shortminus30 & = & \shortminus3x & + & \shortminus3y \\
\hline
& 15 & = & \cancel{0x} & + & 2y \\
& 15 & = & 2y \\[1em]
& 15 & = & 2y \\
& 2 && 2
\end{array}
\end{equation}
\end{document}
I would like to display an horizontal line between the 15 and 2, and between the 2y and 2, as in a division bar. How can I do this?
I tried just using underlines and the like, but they never looked right.
\shortminus
defined?