I am trying to prove ~s=>~p (not s implies not p) given the following 2 premises.
r=>s [r implies s]
(p|q)=>(r|s) [(p or q) implies (r or s)]
I have tried several ways, trying to use OR elimination or Negation Introduction, but I can't even visualize which assumptions I will need to use. Would appreciate any and all help that can be provided.