if you draw a vertical line at x = -1/4 and a horizontal line at y = 4, the intersection of that vertical line and the horizontal line will be the point (-1/2, 4).
of course, you only do that in your head, because it would otherwise clutter up your graph.
i normally do that only to show that the coordinate point is the intersection of the vertical line at x = -1/2 and the horizontal line at y = 4.
here's my graph of that.
the graphing software shows the intersection at (-.5, 4).
