Simplification of propositional formula?

The first step is to exclude negation. NOT (P disjunctive R) logic is equivalent to NOT P conjunct NOT R logic. Look at the right, not P and Q. Through this comparison, we find that the two sub-formulas have the same part, that is, the non-P conjunction #. According to the distribution of disjunctive conjunctions, we can get the logical equivalence between propositional formulas and non-P conjunctions (R disjunctive Q).