а) \(\frac{14a^3b^5}{21a^4b^6} = \frac{2 \cdot 7 \cdot a^3 \cdot b^5}{3 \cdot 7 \cdot a^3 \cdot a \cdot b^5 \cdot b} = \frac{2}{3ab}\)
б) \(\frac{x^2 + x}{x^2} = \frac{x(x + 1)}{x \cdot x} = \frac{x + 1}{x}\)
Ответ: а) \(\frac{2}{3ab}\); б) \(\frac{x+1}{x}\)