Parentheses have a great many specialized meanings in mathematics.

and I've removed the \left and \right parenthesis modifiers, LaTeX source code listing like in professional books.
Drawing Horizontal Lines in LaTeX Posted: 15th August 2009 by Tim in LaTeX Tags: document, horizontal line, horizontal rule, LaTeX, layout, line, page.
As with most other punctuation marks, parentheses should not appear back to back.

Parentheses have special meaning in regular expressions

r markdown - Parentheses under equations with two lines …

Parentheses under equations with two lines of text Rmarkdown

Commas are a small break. Dashes are a bigger break. And parentheses are a bigger break yet. (When I say "parentheses" in this post, I mean the punctuation mark. Personally I use the phrase "parenthetical statement" or "parenthetical remark" to refer to the words themselves.)

Get content between parentheses on two lines

Depending on whether the option is specified ornot, esttab uses two different variants of the CSV format. Bydefault, that is, if plain is omitted, the contents of the tablecells are enclosed in double quotes preceded by an equal sign (i.e.="..."). This prevents Excel from trying to interpret thecontents of the cells and, therefore, preserves formatting elements such asparentheses around t-statistics. One drawback of this approach is, however,that the displayed numbers cannot directly be used for further calculationsin Excel. Hence, if the purpose of exporting the estimates is to doadditional computations in Excel, specify the plain option. In thiscase, the table cells are enclosed in double quotes without the equal sign,and Excel will interpret the contents as numbers. Example:

(if parenthesis in two consequent lines) ..
I have been looking at this code for the past two days now and I can not seem to get it to work

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