If I have an expression A.B'.C.D + (A'+B+C+D') can I write use De Morgan's law on the 2nd part of it to become A.B'.C.D + (A.B'.C'.D)?

Is A'+B+C+D' = A.B'.C'.D??

 

A'+b+c+d' = a'+ ((b+c+d')')' = (a*(b+c+d')')' = (a*b'*(c+d')')' = (a*b'*c'*d)'