X and Y are two variables commonly used in mathematics and science to represent different quantities. X typically denotes the horizontal axis in a graph, while Y represents the vertical axis. These variables help in plotting data points, allowing for visual representation and analysis of relationships between different factors. In many equations, X and Y can be manipulated to find solutions or to understand how changes in one variable affect the other. This relationship is often expressed in the form of a function, where Y is dependent on X, illustrating how one quantity influences another in various contexts.