In the original graph, R (0,3), S(3,3), T(4, -1) and Q(0, 1)
Reflecting it across y=-1, which is a horizontal line going through the point T, all the x coordinates stay the same,
the new confidantes are : R'(0, -5), S'(3, -5), T'(4, -1), Q(0', -3) (Notice; T stays where it is now, because it is right now the line y=-1)
Locate these new points, you have your graph.