1. The problem is to translate the phrase "The difference of x and 12" into a mathematical expression. 2. The phrase "difference" means subtraction. 3. "The difference of x and 12" means subtract 12 from x, which is written as $x - 12$. 4. Other equivalent expressions are "x diminished by 12" and "12 subtracted from x", both meaning the same subtraction operation. 5. Therefore, the mathematical symbol for the phrase is $x - 12$. This completes the translation of the first expression.