The equation "y = g(x)" represents a mathematical function where "y" is the output value, and "g(x)" is the function applied to the input "x." This notation indicates that for each value of "x," there is a corresponding value of "y" determined by the function "g." Functions can take various forms, such as linear, quadratic, or exponential, and they are fundamental in mathematics for modeling relationships between variables. In this context, "g" is often referred to as the function's name, and it can be defined by a specific rule or formula. For example, if g(x) = 2x + 3, then for an input of x = 1, the output would be y = 5. Understanding functions like "y = g(x)" is essential in fields such as science, engineering, and economics, where they help describe real-world phenomena.