19. \(\frac{4}{15}\)(1,5x+\(\frac{3}{8}\))-0,77 (\(\frac{8}{11}\)x-\(\frac{3}{7}\));

Решение:

\[\frac{4}{15}(1,5x + \frac{3}{8}) - 0,77(\frac{8}{11}x - \frac{3}{7}) = \frac{4}{15}(\frac{3}{2}x + \frac{3}{8}) - \frac{77}{100}(\frac{8}{11}x - \frac{3}{7}) = \frac{12}{30}x + \frac{12}{120} - \frac{616}{1100}x + \frac{231}{700} = \frac{2}{5}x + \frac{1}{10} - \frac{14}{25}x + \frac{33}{100} = (\frac{2}{5} - \frac{14}{25})x + (\frac{1}{10} + \frac{33}{100}) = (\frac{10}{25} - \frac{14}{25})x + (\frac{10}{100} + \frac{33}{100}) = -\frac{4}{25}x + \frac{43}{100}\]