4. Упростите выражение: 7 a)+a 18 9 5 7 9 6) 14-3-5a 24 12 16

4. Упростите выражение:

а) $$\frac{7}{18}a + \frac{4}{9}a = \frac{7}{18}a + \frac{4 \cdot 2}{9 \cdot 2}a = \frac{7}{18}a + \frac{8}{18}a = \frac{15}{18}a = \frac{5}{6}a$$

б) $$14 \frac{5}{24}a - 3 \frac{7}{12}a - 5 \frac{9}{16}a = 14 \frac{5}{24}a - 3 \frac{7 \cdot 2}{12 \cdot 2}a - 5 \frac{9 \cdot 1,5}{16 \cdot 1,5}a = 14 \frac{5}{24}a - 3 \frac{14}{24}a - 5 \frac{13,5}{24}a = (14 - 3 - 5)a + \left(\frac{5}{24} - \frac{14}{24} - \frac{13,5}{24}\right)a = 6a + \frac{5 - 14 - 13,5}{24}a = 6a - \frac{22,5}{24}a = 6a - \frac{225}{240}a = 6a - \frac{15}{16}a = \frac{96 - 15}{16}a = \frac{81}{16}a = 5 \frac{1}{16}a$$

Ответ: а) $$\frac{5}{6}a$$, б) $$5 \frac{1}{16}a$$