An x-intercept is the poin where a graph that intercepts the x-axis. The graph can be a linear function (a line), a quadratic function (a parabola), Higher degree functions and so on.
The x-intercept is the point where a line crosses the x-axis. So the x-intercepts for the 3 lines shown in the image provided are (-5,0), (-1,0), and (3, 0). Notice that all x-intercepts have a y-coordinate of zero.
