Equivalence $\displaystyle((\lnot p \lor q) \land (q \lor r)) \land (p \land \lnot q) ≡ c$ I am trying to prove this. Using only laws. I am getting nowhere. The 3 variables on the left hand side keep tripping me up. I've tried DeMorgans, Distributive, Identity and Negation as a starting point but hit dead ends.

Distributing,
$$((\lnot p \lor q)\land (q\lor r)) \iff (((\lnot p \lor q)\land q ) \lor ((\lnot p \lor q)\land r)) \iff q\,\lor ((\lnot p \lor q)\land r)$$
$$\iff (\lnot p \lor q)\land (q\lor r) \iff \lnot(p \land \lnot q)\land (q\lor r)$$
Then the original expression is 
$$\lnot(p \land \lnot q)\land (q\lor r) \land (p\land \lnot q)$$
Which is false. 
