Сократите дробь: a) $$rac{14x^2b^4}{21x^6b^3}$$; б) $$rac{6x}{2x^2-6x}$$; в) $$rac{x^2 - 16}{x - 4}$$.

a) $$rac{14x^2b^4}{21x^6b^3} = \frac{2b}{3x^4}$$

б) $$\frac{6x}{2x^2-6x} = \frac{6x}{2x(x-3)} = \frac{3}{x-3}$$

в) $$\frac{x^2 - 16}{x - 4} = \frac{(x-4)(x+4)}{x-4} = x+4$$