I need help constructing a formal proof of validity for the following:

Question

1. B<->(L•D), ~D, so ~B
2. R v (S•~T), (R v S) -> (U v ~T), so T->U
3. A -> ([E•~G) ->M], ~ (~E v G) -> (M -> F), so A -> [~ (~G -> ~E) ->F