\[3xy \cdot \frac{1}{3}x^{3} - 5y^{2} - 3x^{4}y + 2y^{2} + 5y =\]
\[= x^{4}y - 3x^{4}y - 5y^{2} + 2y^{2} + 5y =\]
\[= - 2x^{4}y - 3y^{2} + 5y.\]