Laurenso
I have this picture
![image.png](/image?hash=bcb78fea68c105b50621108d3f4fe1532862f16df4e482cd5c36d2bf676d9325)

My code

\documentclass[tikz,border=3.14mm]{standalone}
\begin{document}
\begin{tikzpicture}[yscale=.5]
\path[left]
(0,0)     node{$6x^3-2x^2+\phantom{6}x+3$}
++(-90:1) node{$6x^3-6x^2+6x\phantom{{}+3}$}
++(-90:1) node{$12x^3 - 8x^2 + 7x+3$};
\path[left,magenta]
(0,-.5)  ++(180:.2) node{$+$\phantom{$6x^3-2x^2+\phantom{6}x+3$}}
;
\draw[blue]
(0,-1.5)--+(180:3.5);
\end{tikzpicture}
\end{document}


I tried with \usepackage{tabularray}

\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[left=2.00cm, right=2.00cm, top=2.00cm, bottom=2.00cm]{geometry}
\usepackage{amssymb}
\usepackage{hyperref}
\usepackage{mathtools}
\usepackage{amsthm}
\usepackage{tabularray}
\usepackage{ninecolors}
\UseTblrLibrary{amsmath,
booktabs,
counter,
diagbox,
siunitx,
varwidth}
\begin{document}
\begin{tblr}{
colspec={rrrrrrr},
cells={mode=dmath},
hline{Y} = {solid}
}
6x^3  & - & 2x^2&+&x&+&3  \\
6x^3 & - & 6x^2& +&6x\\
12x^3 & - & 8x^2& +&7x&+&3\\
\end{tblr}
\end{document}


![image.png](/image?hash=89df646531ea9e8f421d29cb721ccb4a54abce94a3584ccbf1ff30a4d947c148)

Can I draw this picture by using tabularray?
samcarter
One possible way to draw this is to add an additional column at the front for the + sign:


\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[left=2.00cm, right=2.00cm, top=2.00cm, bottom=2.00cm]{geometry}
\usepackage{amssymb}
\usepackage{hyperref}
\usepackage{mathtools}
\usepackage{amsthm}
\usepackage{tabularray}
\usepackage{ninecolors}
\UseTblrLibrary{amsmath,
booktabs,
counter,
diagbox,
siunitx,
varwidth}
\begin{document}
\begin{tblr}{
colspec={rrrrrrrr},
cells={mode=dmath},
hline{Y} = {solid,blue},
colsep = 0.5mm
}
\SetCell[r=2]{fg=magenta}+ &6x^3  & - & 2x^2&+&x&+&3  \\
&6x^3 & - & 6x^2& +&6x\\
&12x^3 & - & 8x^2& +&7x&+&3\\
\end{tblr}
\end{document}


![Screenshot 2023-06-18 at 16.15.11.png](/image?hash=a6c6739fcef8361094c262ee5b94a8e7201b410f0f5cef9fda24dc8fcbf70f67)
Skillmon
Just using array, multirow, and colortbl (through [table] for xcolor):


\documentclass[border=3.14]{standalone}

\usepackage[table]{xcolor}
\usepackage{array}
\usepackage{multirow}
\setlength\extrarowheight{1pt}

\begin{document}
$\begin{array}{*{4}{@{} >{{}}c<{{}} @{} r }} & 6x^3 & - & 2x^2 & + & x & + & 3 \\ \multirow{-2}{*}{$\!\mathcolor{magenta}{{}+{}}$} & 6x^3 & - & 6x^2 & + & 6x & \\ \arrayrulecolor{blue} \hline & 12x^3 & - & 8x^2 & + & 5x & + & 3 \\ \end{array}$
\end{document}


![tabularthingy-1.png](/image?hash=b7dac4c671d4b9caea79273cdf5bb0d056e180b5c433bd5c10639ffc811109ae)

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