title: Parentheses under equations with two lines of text Rmarkdown
body: <p>I would like to write in a Rmarkdown document an equation with some explanations below it. I have found the functions <code>\underbrace{}</code> coupled with <code>_\textrm{}</code>.</p>
  
  <pre><code>\underbrace{X}_\textrm{Text1 for X} = \underbrace{Y}_\textrm{Text1 for Y}
  </code></pre>
  
  <p>This is working perfectly fine for me. What I would like to add is a second text line for the variable X and Y. I tried splitting the text inside <code>\textrm{}</code> and adding a new term <code>\textrm{}</code>. But none of those solutions worked. Does anyone have an idea? </p>