x-intercept

The x-intercept is where a graph crosses the x-axis — the spot where its height is exactly zero. If the graph showed your savings shrinking, the x-intercept would mark the moment you hit empty.

Because it lies on the x-axis, an x-intercept always has the form (a, 0). You find it by setting y = 0 and solving for x. For this reason the x-intercepts of a function are the same thing as its roots or zeros.

A line has at most one x-intercept, but other graphs can have many or none. A parabola, for example, may cross the x-axis twice, just touch it once, or miss it entirely.