2. $$rac{8x^7y(a+b)}{22x^{13}y^3(a+b)}$$

$$\frac{8x^7y(a+b)}{22x^{13}y^3(a+b)} = \frac{8}{22} \cdot \frac{x^7}{x^{13}} \cdot \frac{y}{y^3} \cdot \frac{(a+b)}{(a+b)} = \frac{4}{11} \cdot \frac{1}{x^{13-7}} \cdot \frac{1}{y^{3-1}} \cdot 1 = \frac{4}{11} \cdot \frac{1}{x^6} \cdot \frac{1}{y^2} = \frac{4}{11x^6y^2}$$

Ответ: $$\frac{4}{11x^6y^2}$$