40. Сократите: 1) $$\frac{9 \cdot 16}{46 \cdot 46}$$; 2) $$\frac{8 \cdot 27}{8 \cdot 28}$$; 3) $$\frac{2 \cdot 3 \cdot 5}{4 \cdot 9 \cdot 25}$$; 4) $$\frac{7 \cdot 13 - 7 \cdot 2}{35 \cdot 9 + 35 \cdot 2}$$

Решение: 1) $$\frac{9 \cdot 16}{46 \cdot 46} = \frac{9 \cdot 16}{2116} = \frac{144}{2116} = \frac{36}{529}$$ 2) $$\frac{8 \cdot 27}{8 \cdot 28} = \frac{27}{28}$$ 3) $$\frac{2 \cdot 3 \cdot 5}{4 \cdot 9 \cdot 25} = \frac{30}{900} = \frac{1}{30}$$ 4) $$\frac{7 \cdot 13 - 7 \cdot 2}{35 \cdot 9 + 35 \cdot 2} = \frac{7(13-2)}{35(9+2)} = \frac{7 \cdot 11}{35 \cdot 11} = \frac{7}{35} = \frac{1}{5}$$