We are told that there are currently 200 shirts
If each shirt is sold for $14, then the total revenue will be
[tex]200\times\text{ \$14= \$2800}[/tex]Therefore, we can conclude that the revenue formula is
[tex]\text{Revenue}=\text{Number of shirts}\times unit\text{ cost}[/tex]From the question, we are told
[tex]\begin{gathered} \text{Number of shirts reduces by 9 for every one dollar increment} \\ \text{Thus, we have} \\ 200-9x \end{gathered}[/tex]Similarly, the cost will be
[tex]x+14[/tex]Therefore, the total revenue will be defined by
[tex]\begin{gathered} \text{Total }Revenue=\text{Revenue}=\text{Number of shirts}\times unit\text{ cost=}\lbrack(x+14)\times(200-9x)\rbrack \\ \text{Total }Revenue=\lbrack(x+14)\times(200-9x)\rbrack \end{gathered}[/tex]