#11=-xy^2-(xy)/(2x-y)#
#11(2x-y)=-xy^2(2x-y)-xy#
#22x-11y=-2x^2y^2+xy^3-xy#
#22-11dy/dx=-4xy^2-4x^2y dy/dx+y^3+3xy^2 dy/dx-y-xdy/dx#
#4x^2y dy/dx-3xy^2 dy/dx+xdy/dx-11dy/dx=y^3-4xy^2-y-22#
#dy/dx(4x^2y -3xy^2 +x-11)=y^3-4xy^2-y-22#
#dy/dx=(y^3-4xy^2-y-22)/(4x^2y -3xy^2 +x-11)#