Thực hiện phép tính: a) \(\frac{{24{y^5}}}{{7{x^2}}}.\left( { - \frac{{12{y^3}}}} \right)\); b) \( - \frac{{36{y^3}}}{{15{x^4}}}.\left( { - \frac{{45{x^2}}}{{9{y^3}}}} \right)\); c) \(\frac{{{x^2} - {y^2}}}{{{x^2}}}.\frac{{{x^4}}}{{{{\left( {x + y} \right)}^2}}}\); d) \(\frac{{{x^2} - 1}}.\frac}\).

Thực hiện phép tính:

a) \(\frac{{24{y^5}}}{{7{x^2}}}.\left( { - \frac{{12{y^3}}}} \right)\);

b) \( - \frac{{36{y^3}}}{{15{x^4}}}.\left( { - \frac{{45{x^2}}}{{9{y^3}}}} \right)\);

c) \(\frac{{{x^2} - {y^2}}}{{{x^2}}}.\frac{{{x^4}}}{{{{\left( {x + y} \right)}^2}}}\);

d) \(\frac{{{x^2} - 1}}.\frac}\).