20 votes

22 votes

1

x' + xy = x'(y+y') + xy

=x'y + x'y' + xy

=x'y + x'y + x'y' + xy (because AB+AB+AB+.......................=AB)

=(x'y + x'y') + (x'y + xy)

=x'(y+y') + y(x+x')

=x'+y

=x'y + x'y' + xy

=x'y + x'y + x'y' + xy (because AB+AB+AB+.......................=AB)

=(x'y + x'y') + (x'y + xy)

=x'(y+y') + y(x+x')

=x'+y