4. Вычислите: a) 518·52·5 519; б) 311·27 96.

a) $$\frac{5^{18} \cdot 5^2 \cdot 5}{5^{19}} = \frac{5^{18+2+1}}{5^{19}} = \frac{5^{21}}{5^{19}} = 5^{21-19} = 5^2 = 25$$ б) $$\frac{3^{11} \cdot 27}{9^6} = \frac{3^{11} \cdot 3^3}{(3^2)^6} = \frac{3^{11+3}}{3^{12}} = \frac{3^{14}}{3^{12}} = 3^{14-12} = 3^2 = 9$$ Ответ: а) 25, б) 9