Please provide answers to the following three exercises/questions.
1. Please provide a natural deduction proof for the following valid, deductive argument:
Premise 1: ~ ( F & A )
Premise 2: ~ ( L v ~ A )
Premise 3: D > ( F v L ) / ~ D
2. Answer the following question: can one invalidity with the natural deduction proof method? Why or why not?
3. Answer the following the question: can one construct a natural deduction proof for an invalid argument in SL? Why or why not?