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.