Решить уравнения: 1) (5/8 + 2/3) * x = 5/4 - 7/18; 2) (5 3/8 - 3 7/12) * u = 4 5/6 + 9/10; 3) y * (1 4/5 + 2 3/4 - 3 7/10) = 25/48 + 2 2/3; 4) (1 11/14 + 28/3 * 5/8) * z = 2 2/21 - 2/3

1) $(\frac{5}{8} + \frac{2}{3}) \cdot x = \frac{5}{4} - \frac{7}{18}$ $(\frac{15+16}{24}) \cdot x = \frac{45-14}{36}$ $\frac{31}{24} \cdot x = \frac{31}{36}$ $x = \frac{31}{36} : \frac{31}{24} = \frac{31 \cdot 24}{36 \cdot 31} = \frac{24}{36} = \frac{2}{3}$ Ответ: $x = \frac{2}{3}$ 2) $(5\frac{3}{8} - 3\frac{7}{12}) \cdot u = 4\frac{5}{6} + \frac{9}{10}$ $(5\frac{9}{24} - 3\frac{14}{24}) \cdot u = 4\frac{25}{30} + \frac{27}{30}$ $1\frac{19}{24} \cdot u = 4\frac{52}{30} = 5\frac{22}{30} = 5\frac{11}{15}$ $\frac{43}{24} \cdot u = \frac{86}{15}$ $u = \frac{86}{15} : \frac{43}{24} = \frac{86 \cdot 24}{15 \cdot 43} = \frac{2 \cdot 24}{15} = \frac{16}{5} = 3\frac{1}{5}$ Ответ: $u = 3,2$ 3) $y \cdot (1\frac{4}{5} + 2\frac{3}{4} - 3\frac{7}{10}) = \frac{25}{48} + 2\frac{2}{3}$ $y \cdot (1\frac{16}{20} + 2\frac{15}{20} - 3\frac{14}{20}) = \frac{25}{48} + 2\frac{32}{48}$ $y \cdot (3\frac{31}{20} - 3\frac{14}{20}) = 2\frac{57}{48}$ $y \cdot \frac{17}{20} = 3\frac{9}{48} = 3\frac{3}{16}$ $y \cdot \frac{17}{20} = \frac{51}{16}$ $y = \frac{51}{16} : \frac{17}{20} = \frac{51 \cdot 20}{16 \cdot 17} = \frac{3 \cdot 5}{4} = \frac{15}{4} = 3\frac{3}{4}$ Ответ: $y = 3,75$ 4) (1\frac{11}{14} + \frac{28}{3} \cdot \frac{5}{8}) \cdot z = 2\frac{2}{21} - \frac{2}{3}$ $(\frac{25}{14} + \frac{7 \cdot 5}{3 \cdot 2}) \cdot z = 2\frac{2}{21} - \frac{14}{21}$ $(\frac{25}{14} + \frac{35}{6}) \cdot z = 1\frac{23}{21} - \frac{14}{21}$ $(\frac{75+245}{42}) \cdot z = 1\frac{9}{21} = 1\frac{3}{7}$ $\frac{320}{42} \cdot z = \frac{10}{7}$ $\frac{160}{21} \cdot z = \frac{10}{7}$ $z = \frac{10}{7} : \frac{160}{21} = \frac{10 \cdot 21}{7 \cdot 160} = \frac{3}{16}$ Ответ: $z = \frac{3}{16}$