2x^3y*(-6y)^2+(-5xy)^2*(xy)-xy^3*(-2x)^2
=2x^3y*(36y^2)+(25x^2y^2)*(xy)-xy^3(4x^2)
=72x^3y^3+25x^3y^3-4x^3y^3
=(72+25-4)x^3y^3
=93x^3y^3