The function "g(a)" represents a mathematical expression where "g" is a function and "a" is its input variable. In this context, "g" can take various forms, such as linear, quadratic, or exponential, depending on how it is defined. The output of "g(a)" is determined by substituting the value of "a" into the function. Functions like "g(a)" are fundamental in mathematics and are used in various fields, including physics, economics, and engineering. They help model relationships between variables, allowing for predictions and analysis based on different input values. Understanding functions is essential for solving equations and interpreting data.