3-x/3^3×xy-x/3-x+3-y/3x^2=
=1/x^3×x×(y-1)+3y-y/3x2=
=y-1/x^2+3-y/3x^2=
=3(y-1)+3-y/3x^2=
=3y-3+3-y/3x^2=
=2y/3x^2
3-x/3^3×xy-x/3-x+3-y/3x^2=
=1/x^3×x×(y-1)+3y-y/3x2=
=y-1/x^2+3-y/3x^2=
=3(y-1)+3-y/3x^2=
=3y-3+3-y/3x^2=
=2y/3x^2