Rút gọn mỗi phân thức sau: a) \(\frac{{25{x^2}{y^3}}}{{35{x^3}{y^2}}}\); b) \(\frac\); c) \(\frac{{{{\left( { - x} \right)}^5}{y^2}}}{{{x^2}{{\left( { - y} \right)}^3}}}\); d) \(\frac{{{x^2} - 2x}}{{{x^3} - 4{x^2} + 4x}}\).

Rút gọn mỗi phân thức sau:

a) \(\frac{{25{x^2}{y^3}}}{{35{x^3}{y^2}}}\);

b) \(\frac\);

c) \(\frac{{{{\left( { - x} \right)}^5}{y^2}}}{{{x^2}{{\left( { - y} \right)}^3}}}\);

d) \(\frac{{{x^2} - 2x}}{{{x^3} - 4{x^2} + 4x}}\).