Dave, Vahid, and Abbas are deciding whether to assign an extra difficult homework in each of their respective classes. Two students, hypothetically named Steve and Yida, are discussing the situation. Steve says $$If Vahid assigns it and Dave does, then Abbas will, too.$$ Yida replies $$If Abbas doesn$$t assign it but Dave does, then Vahid won$$t$.$ Prove using the laws of propositional logic that their two statements are equivalent. Use variables D$,$ V $,$ and A as Dave, Vahid or Abbas assigns an extra difficult homework respectively.