# Square Brackets beneath Content in Math-Mode [duplicate]

I need some help:

Is it anyhow possible in Latex to make some square brackets under some Math-Text like:

2x^2 + 4x - 3 = 0

|_____|

I know about the underbrace-command but I need square brackets.

I hope that someone can help me.

## marked as duplicate by Henri Menke, Stefan Pinnow, Troy, Kurt, TeXnicianMay 20 '18 at 11:51

like this:

with use of mathtools:

\documentclass{article}
\usepackage{mathtools}

\begin{document}
$\underbracket{2x^2} + 4x - 3 = 0$
$\underbracket[0.5pt][5pt]{2x^2} + 4x - 3 = 0$
\end{document}


for more details see documentation for the package mathtools, page 13