A converging lens forms a real image of an object at a distance \(d_i\) behind the lens. A transparent glass plate of thickness \(t\) and refractive index \(n\) (where \(n > 1\)) is inserted between the lens and the image, with its flat faces perpendicular to the optical axis. Using the small-angle (paraxial) approximation, which of the following expressions represents the distance \(\Delta x\) by which the real image is displaced away from the lens along the optical axis?