Выполни действия с алгебраическими дробями

1. \(\dfrac{a^2-ab}{x^2+xy} \cdot \dfrac{x^3+x^2y}{a-b} = \) [ ];
2. \(\dfrac{x^2+8x+16}{3x-9} \cdot \dfrac{x^2-9}{3x+12} = \) [ ];
3. \(\dfrac{2y-7}{22a^2b^2} : \dfrac{4y^2-49}{11ab^3} = \) [ ];
4. \(\dfrac{x^2-6x+9}{9x^3} : \dfrac{x^2-9}{9x} = \) [ ];
5. \(\dfrac{25t-t^3}{25t^2} \cdot \dfrac{10t^4}{t^2-10t+25} = \) [ ].