如题所述
Y=A+A'B+A'B'C+A'B'C'D
Y=A+A'(B+B'C+B'C'D)
Y=A+(B+B'C+B'C'D)
Y=A+B+B'(C+C'D)
Y=A+B+C+C'D
Y=A+B+C+D