Thu gọn các biểu thức sau: (a) 5x^3y^2+4x^2y^2−x^3+8x^2y^2−5x^3y^2. (b) (−3x^3y+5x^2y^4−1)⋅2xy^3.

a) \(\begin{array}{l}5{x^3}{y^2} + 4{x^2}{y^2} - {x^3} + 8{x^2}{y^2} - 5{x^3}{y^2}\\ = 12{x^2}{y^2} - {x^3}\end{array}\)

b) \(\begin{array}{l}\left( { - 3{x^3}y + 5{x^2}{y^4} - 1} \right) \cdot 2x{y^3}\\ = - 6{x^4}{y^4} + 10{x^3}{y^7} - 2x{y^3}\end{array}\)

c) \(\begin{array}{l}\left( {{x^3}{y^3} - \frac{1}{2}{x^2}{y^3} - {x^3}{y^2}} \right):(\frac{1}{3}{x^2}{y^2})\\ = 3xy - \frac{3}{2}y - 3x\end{array}\)

d) \(\begin{array}{l}(x - 5)(3 - x)\\ = - {x^2} + 8x - 15\end{array}\)