Incorrect Answer.
Recalling the notion of semantic entailment, the relationship (p 
q) 
r, r 
p holds if, and only if, p computes to T whenever the
formulas (p q) r and r evaluate to T. As done for
tautology-checking, we ask whether this relationship can be
violated. For that, p has to
evaluate to F, while (p q) r and r evaluate to T. But this
forces p and r to be true. Since this assignment of truth values makes
(p q) r and r true and p
false, we conclude that the condition for semantic entailment is
indeed violated.
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