use propositional logic to prove that the argument is valid. do not use truth tables   ((¬A∨¬B)→(C∧D))∧¬D ∴ B

What is the difference between ‘⊢’ and ‘⊨’. In giving your answer, briefly describe the  two (equivalent) notions of validity we have given for truth-functional logic. (2-4  sentences

For each of the attached probabilistic expressions, please answer "yes" or "no" to indicate if it is equal to P(A,B,C), given Boolean random variables A, B and C , and no independence or conditional independence are assumed between any of them.