songdiandian
Newbie level 2
the (b), i think it's not necessary to distributive expression,because it will became complex.my way is like this:
F'={EXPRESSION}'，On the basis of Demorgan's defining,F'=ABD+A'BC+AB'D+B'CD,optimized,then F'=AD+A'BC+B'CD.use Demorgan's defining again.
F''=F=(A'+D')(A'+B+D')(B+C'+D').This is probably the answer of the question.but F=(C'+D')(A'+D')(A+B'+C') is the correct answer.why?