What is the y-intercept in a graph?

The y-intercept of a graph is defined as the y-coordinate of the point where the graph crosses the y-axis. When a line or curve intersects the y-axis, the corresponding x-coordinate at that point is always zero. Thus, the y-intercept provides crucial information about the function’s value when the input (x) is zero. This concept is fundamental in understanding linear equations where the y-intercept is often denoted as "b" in the slope-intercept form of a line (y = mx + b). Recognizing the y-intercept is essential for graphing functions and determining their behavior at specific points, particularly when analyzing linear relationships or applications in various mathematical contexts.