Решить уравнения письменно, хелп (да, это опять я:>)

3) а)
$3.8(b - 1 \frac{1}{6} ) = \frac{19}{20} \\ b - 1 \frac{1}{6} = \frac{19}{20} \div 3.8 \\ b - 1 \frac{1}{6} = \frac{19}{20} \div \frac{38}{10} \\ b - 1 \frac{1}{6} = \frac{19}{20} \times \frac{10}{38} \\ b - 1 \frac{1}{6} = \frac{1}{4} \\ b = \frac{1}{4} + 1 \frac{1}{6} = \frac{1}{4} + \frac{7}{6} = \frac{3}{12} + \frac{14}{12} = \frac{17}{12} = 1 \frac{5}{12}$
б)
$1 \frac{1}{4} (y - 1.2) = 5.5 \\ y - 1. 2 = 5.5 \div 1 \frac{1}{4} \\ y - 1. 2 = \frac{55}{10} \div \frac{5}{4} \\ y - 1.2 = \frac{11}{2} \times \frac{4}{5} \\ y - 1.2 = \frac{22}{5} \\ y - 1. 2 = 4.4 \\ y = 4.4 + 1.2 = 5.6$
4)
а)
$(m - \frac{3}{7} ) \div 1 \frac{1}{5} = 3.5 \\ m - \frac{3}{7} = 3.5 \times 1 \frac{1}{5} \\ m - \frac{3}{7} = \frac{35}{10} \times \frac{6}{5} \\ m - \frac{3}{7} = \frac{21}{5} \\ m = \frac{21}{5} + \frac{3}{7} = \frac{147}{35} + \frac{15}{35} = \frac{162}{35} = 4 \frac{22}{35}$
б)
$(2.3 - m) \div \frac{3}{5} = 0.12 \\ 2.3 - m = 0.12 \times \frac{3}{5} \\ 2.3 - m = \frac{12}{100} \times \frac{3}{5} \\ 2.3 - m = \frac{36}{500} \\ 2.3 - m = 0.072 \\ m = 2.3 - 0.072 = 2.228$