Dennis and Eduardo are studying transformations using triangles. Triangle ABC and triangle DEF are plotted in a coordinate plane. Dennis notices that if he reflects triangle ABC across the y-axis and then translates it down 4 units, the result is triangle Def. Eduardo says that he can first translate triangle ABC down 4 units and then reflect it across the y-axis in order to get triangle Def. Is Eduardo correct? Explain your answer and tell whether triangle abc and def are congruent.