1) x + 2x + 3x + 4x = 48;

1) $x + 2x + 3x + 4x = 48$ $10x = 48$ $x = 48 : 10$ $x = 4,8$ 2) $3,2y - 1,4y + y - 0,6y = 5,5$ $(3,2 - 1,4 + 1 - 0,6)y = 5,5$ $2,2y = 5,5$ $y = 5,5 : 2,2$ $y = 2,5$ 3) $1\frac{3}{5}z + z - \frac{4}{15}z + \frac{7}{6}z = 2\frac{1}{3}$ Приведем к общему знаменателю 30: $\frac{48}{30}z + \frac{30}{30}z - \frac{8}{30}z + \frac{35}{30}z = \frac{7}{3}$ $\frac{105}{30}z = \frac{7}{3}$ $\frac{7}{2}z = \frac{7}{3}$ $z = \frac{7}{3} : \frac{7}{2} = \frac{7}{3} \cdot \frac{2}{7} = \frac{2}{3}$ 4) $2x + 5 + x + 14 + 6x = 64$ $(2x + x + 6x) + (5 + 14) = 64$ $9x + 19 = 64$ $9x = 64 - 19$ $9x = 45$ $x = 5$ 5) $1,8 + 3,5y + 0,9 + y = 16,2$ $(3,5y + y) + (1,8 + 0,9) = 16,2$ $4,5y + 2,7 = 16,2$ $4,5y = 16,2 - 2,7$ $4,5y = 13,5$ $y = 13,5 : 4,5$ $y = 3$ 6) $4\frac{1}{2}z + \frac{7}{9}z + 2\frac{1}{3} + \frac{1}{6}z = 5\frac{1}{18}$ Сгруппируем слагаемые с $z$ и без: $(4\frac{1}{2} + \frac{7}{9} + \frac{1}{6})z + 2\frac{1}{3} = 5\frac{1}{18}$ Приведем дроби к знаменателю 18: $(4\frac{9}{18} + \frac{14}{18} + \frac{3}{18})z + 2\frac{6}{18} = 5\frac{1}{18}$ $(4\frac{26}{18})z + 2\frac{6}{18} = 5\frac{1}{18}$ $5\frac{8}{18}z + 2\frac{6}{18} = 5\frac{1}{18}$ $5\frac{4}{9}z = 5\frac{1}{18} - 2\frac{6}{18}$ $5\frac{4}{9}z = 4\frac{19}{18} - 2\frac{6}{18} = 2\frac{13}{18}$ $\frac{49}{9}z = \frac{49}{18}$ $z = \frac{49}{18} : \frac{49}{9} = \frac{49}{18} \cdot \frac{9}{49} = \frac{9}{18} = \frac{1}{2}$