Đáp án:
`x²(4x³ - 5xy + 2x)(\frac{-1}{2}xy)`
`= [x² . 4x³ + x² . (-5xy) + x² . 2x](\frac{-1}{2}xy)`
`= [4x^{5} - 5x³y + 2x³](\frac{-1}{2}xy)`
`= 4x^{5} . (\frac{-1}{2}xy) + (-5x³y) . (\frac{-1}{2}xy) + 2x³ . (\frac{-1}{2}xy)`
`= -2x^{6}y + \frac{5}{2}x^{4}y² - x^{4}y`
Chúc học tốt!!!