need help with boolean algebra (logics)

Question

for boolean algebra, what is the contrapositive of an "all" statement and an "some not" statement

Answer 1

Since the contrapositive of the implication $p \implies q$ is $\neg q \implies \neg p$, you first want to rewrite your statements as an implication. So "All politicians are liers" becomes "If X is a politician, then X is a liar", and the contrapositive is "If X is not a liar, then X is not a politician".