The relationship between \( y = f(x) \) and \( y = f(-x) \) represents a transformation known as a reflection. Specifically, this transformation is a reflection over the y-axis on the graph.
This means that every point of \( y = f(-x) \) is the mirror image of the corresponding point of \( y = f(x) \) across the y-axis. For example, if the point \( (a, b) \) lies on the graph of \( y = f(x) \), then the point \( (-a, b) \) will lie on the graph of \( y = f(-x) \).