Regression equation questions

Question

I would like to use something, maybe a. b. or (1) (2) to show which equation correlates with which part of the table. Also it will be nice to be able to reference the various models in my discussion. I looked at another thread but their tip of using /label{} didn't really work.

Here's the code:

\documentclass[twocolumn]{article}

\usepackage{booktabs, makecell, tabularx}
\renewcommand\theadfont{\normalsize}
\renewcommand\theadgape{}
\setcellgapes{2pt}
\newcolumntype{L}{>{\raggedright\arraybackslash}X}
\usepackage{caption}
\usepackage{textcomp}
\usepackage{graphicx}
\raggedbottom
\usepackage{amsmath,geometry}
\usepackage{rotating}
\usepackage{booktabs, makecell}
\usepackage[referable]{threeparttablex}
\usepackage{siunitx}
\usepackage[skip=1ex]{caption}
\usepackage{upquote}
\usepackage{balance}
\usepackage[lite]{mtpro2} % Times Roman math font

\begin{document}

$\text{CEO Salary} = 
  \beta_0 + 
  \beta_1\,\text{return} + 
  \beta_2\,\text{bonus} + 
  \beta_3\,\text{stock awards} + 
  \beta_4\,\text{option awards} +
  \beta_5\,\text{other compensation} 
  \beta_6\,\text{age} +
  \beta_7\,\text{age sq} +
  \beta_8\,\text{male} +
  \beta_9\,\text{industry} +
  \beta_{10}\,\text{volume} $ \label{eqn:first}

  $\text{Total Compensation} = 
  \beta_0 + 
  \beta_1\,\text{return} + 
  \beta_2\,\text{age} + 
  \beta_3\,\text{male} + 
  \beta_4\,\text{interaction term?} +
  \beta_5\,\text{industry} 
  \beta_6\,\text{volume} +
  \beta_7\,\text{age sq} +
  \beta_8\,\text{male} +
  \beta_9\,\text{industry} +
  \beta_{10}\,\text{volume} $ \label{eqn:second} 

\end{document}