Сокращение дробей

1. a) $$rac{24xy^7}{32x^3y^4} = rac{3 cdot 8 cdot x cdot y^4 cdot y^3}{4 cdot 8 cdot x cdot x^2 cdot y^4} = rac{3y^3}{4x^2}$$

2. б) $$rac{7a^2+21a}{14a} = rac{7a(a+3)}{14a} = rac{a+3}{2}$$

3. в) $$rac{b^2-64}{5b-40} = rac{(b-8)(b+8)}{5(b-8)} = rac{b+8}{5}$$