Сокращение дробей

1. a) $$rac{12a^6b}{27a^2b^3} = rac{4a^4}{9b^2}$$
2. б) $$rac{3x^2-15x}{15x} = rac{3x(x-5)}{15x} = rac{x-5}{5}$$
3. в) $$rac{x^2-16}{2x-8} = rac{(x-4)(x+4)}{2(x-4)} = rac{x+4}{2}$$