Rút gọn biểu thức dưới đây

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6/ \( -\frac{2}{3} x^3 y \left( -\frac{3}{4} x^2 y^3 + \frac{1}{3} xy - 1 \right) \)

7/ \( -3x^5 y^7 \left( \frac{2}{3} x^4 y^{-3} + \frac{1}{2} \right) \)

8/ \( \frac{3}{5} x^2 y \left( -\frac{5}{3} xy - 10x + 5y \right) \)

9/ \( -\frac{5}{6} x \left( \frac{2}{3} x^2 y^4 + \frac{3}{4} xy^2 - 1/2 xy \right) \)

10/ \( x^4 y^5 \left( \frac{7}{3} x^2 y^4 - \frac{1}{7} x^3 y - \frac{5}{14} \right) \)