You can
put this solution on YOUR website! Note: I'm going to use the & symbol for the •
So (Q • ~R) -> S = (Q & ~R) -> S
1. P v Q
2.(Q & ~R) -> S
3. R -> P
4. ~P / S
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5. ~R 3,4 Modus Tollens
6. Q 1,4 Disjunctive Syllogism
7. Q & ~R 5,6 Conjunction
8. S 2,7 Modus Ponens