An implicit equation is a mathematical expression that defines a relationship between variables without explicitly solving for one variable in terms of the other. For example, the equation x² + y² = 1 describes a circle, where both x and y are interdependent. This means you can find points on the circle without isolating y. In contrast to explicit equations, which clearly express one variable as a function of another (like y = 2x + 3), implicit equations can represent more complex shapes and relationships. They are commonly used in fields like geometry, physics, and engineering to model various phenomena.