19) $$\frac{8}{15}(3-\frac{3}{4}x-\frac{5}{16}y) - \frac{3}{20}(6-\frac{2}{3}x-4\frac{4}{9}y) =$$

19) $$\frac{8}{15}(3-\frac{3}{4}x-\frac{5}{16}y) - \frac{3}{20}(6-\frac{2}{3}x-4\frac{4}{9}y) =$$

$$\frac{8}{15} \cdot 3 - \frac{8}{15} \cdot \frac{3}{4}x - \frac{8}{15} \cdot \frac{5}{16}y - \frac{3}{20} \cdot 6 + \frac{3}{20} \cdot \frac{2}{3}x + \frac{3}{20} \cdot \frac{40}{9}y =$$

$$\frac{8}{5} - \frac{2}{5}x - \frac{1}{6}y - \frac{9}{10} + \frac{1}{10}x + \frac{2}{3}y =$$

$$\frac{16}{10} - \frac{9}{10} - \frac{4}{10}x + \frac{1}{10}x - \frac{1}{6}y + \frac{4}{6}y =$$

$$\frac{7}{10} - \frac{3}{10}x + \frac{3}{6}y =$$

$$\frac{7}{10} - \frac{3}{10}x + \frac{1}{2}y$$

Ответ: $$\frac{7}{10} - \frac{3}{10}x + \frac{1}{2}y$$