Natural Deduction: $p \to (\neg q \leftrightarrow (r \lor s)), \neg s \vdash (p \land \neg q) \to r$
Natural Deduction: $(p \lor q)\to r\vdash p \to r$ and $p\to\neg q\leftrightarrow(r\lor s),\neg s\vdash (p\land \neg q)\to r$