It looks like there might be a formatting issue in your expression. If you meant to simplify \( 54 - \sqrt{3} \), this expression is already in its simplest form.
However, if you intend to express it in a different way or if you meant \( 54 - (-\sqrt{3}) \), that would simplify to \( 54 + \sqrt{3} \).
Please clarify the expression you would like to simplify!