The expression "-x" represents the negation of a variable or value "x." In mathematics, this means that if "x" is a positive number, "-x" will be its negative counterpart. For example, if "x" equals 5, then "-x" equals -5. This concept is fundamental in algebra and is used in various equations and functions. Negation is an important operation in many fields, including computer science and logic. In programming, the negation of a boolean value can change true to false and vice versa. Understanding how to manipulate expressions like "-x" is essential for solving problems and developing algorithms in computer science.