I wish to reduce the expression $A'B'+AB'+BC'D'$ to its simplest form.
The notation for boolean variables $A,B,C,D$, for those who are not familiar, is :
$+$ for logical OR operation
$'$ for the logical NOT operation, and
$AB$ means $A$ logical AND $B$
The answer is B’ + C’D’, and my attempt at the solution is:
$A'B'(B+B') +AB'+BC'D'$
$\equiv AB'B+A'B'B'+AB'+BC'D'$
$\equiv A'+AB'+A'B'+BC'D'$
$\equiv A'+B'+A'B'+BC'D'$
Here I am stuck. Any help much appreciated.