[tex]10xy^2(3x^3-5x)-2x^2y(6y^3+3y)=\\\\=30x^4y^2-50x^2y^2-12x^3y^4-6x^2y^2=\\\\=\boxed{30x^4y^2-12x^3y^4-56x^2y^2}[/tex]
