Сократите дробь: a) 12a⁶b / 27a²b³; б) (3x² - 15x) / 15x; в) (x² - 16) / (2x - 8).

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