# DNF and CNF missing law/rule

I have tried simplify some expressions to DNF and CNF but I'm stuck in one step and I can't find some rule or law what can I apply on it. I used Wolfram and found that my expression is not in DNF/CNF yet.

On DNF I'm stuck here: but the DNF is:

On CNF I'm stuck here:

but the CNF from calculators is:

Please can someone help me with some tip, rule or law what can by applied to solve the problem? I spent hours with it but with no progress.

Try:

$$PQ+PQ'=P$$

and

Absorption

$$P+PQ=P$$

$$C'D'+CD+B'D'+BD \overset{Adjacency \ x \ 2}{=}$$
$$BC'D'+B'C'D'+CD+B'D'+BCD+BC'D \overset{Absorption \ x \ 2}{=}$$
$$BC'D'+CD+B'D'+BC'D \overset{Adjacency}{=}$$
$$BC'+CD+B'D'$$
• @kampus For the CNF: The $A + B'+C+D)$ term gets absorbed by the $A + C+D$ term, and the $A+B'+C'+D'$ term gets absorbed by the $A + C'+D'$ term. Also, I note that there are two $B+C'+D'$ terms at the end .. one can be eliminated by Idempotence. – Bram28 Sep 28 '18 at 17:18