Thực hiện phép tính: (a) (4x^2y^3+8x−4y)⋅(1/4y).

a) \(\left( {4{x^2}{y^3} + 8x - 4y} \right) \cdot \left( {\frac{1}{4}y} \right)\)

\( = 4{x^2}{y^3} \cdot \frac{1}{4}y + 8x \cdot \frac{1}{4}y - 4y \cdot \frac{1}{4}y\)

\( = {x^2}{y^4} + 2xy - {y^2}\)

b) \(\left( {{x^6}{y^6} + 5{x^4}{y^4} - 6{x^3}{y^3}} \right):\left( { - {x^3}{y^3}} \right)\)

\( = \left( {{x^6}{y^6}} \right):\left( { - {x^3}{y^3}} \right) + \left( {5{x^4}{y^4}} \right):\left( { - {x^3}{y^3}} \right) - \left( {6{x^3}{y^3}} \right):\left( { - {x^3}{y^3}} \right)\)

\( = - {x^3}{y^3} - 5xy + 6\).