Решите уравнение 2 7/9: (3 3/4у-11 2/3)+1 6/7=2 4/21

$2 \frac{7}{9} : (3 \frac{3}{4}y - 11 \frac{2}{3} ) + 1 \frac{6}{7} = 2 \frac{4}{21} \\ \\ 2 \frac{7}{9} : (3 \frac{3}{4}y - 11 \frac{2}{3} ) = 2 \frac{4}{21} -1 \frac{6}{7} \\ \\ 2 \frac{7}{9} : (3 \frac{3}{4}y - 11 \frac{2}{3} ) = 2 \frac{4}{21} -1 \frac{18}{21} \\ \\ (3 \frac{3}{4}y - 11 \frac{2}{3} ) = 2 \frac{7}{9} : \frac{1}{3} \\ \\ 3 \frac{3}{4}y- 11 \frac{2}{3} = \frac{25}{3} \\ \\ 3 \frac{3}{4}y= 8 \frac{1}{3} + 11 \frac{2}{3} \\ \\$
$y= 20 : 3 \frac{3}{4}= \frac{20}{1} * \frac{4}{15} = \frac{4*4}{1*3} \\ \\ y= 5 \frac{1}{3}$

проверим:
$2 \frac{7}{9} : (3 \frac{3}{4}* 5 \frac{1}{3} - 11 \frac{2}{3} ) + 1 \frac{6}{7} = 2 \frac{4}{21} \\ \\ 2 \frac{7}{9} : (3 \frac{3}{4}* 5 \frac{1}{3} - 11 \frac{2}{3} ) + 1 \frac{6}{7} = 2 \frac{4}{21} \\ \\ 2 \frac{7}{9} : (20 - 11 \frac{2}{3} ) + 1 \frac{6}{7} = 2 \frac{4}{21} \\ \\ 2 \frac{7}{9} : 8 \frac{1}{3} + 1 \frac{6}{7} = 2 \frac{4}{21} \\ \\ \frac{25}{9} * \frac{3}{25} + 1 \frac{6}{7} = 2 \frac{4}{21} \\ \\ \frac{1}{3} + 1 \frac{6}{7} = 2 \frac{4}{21} \\ \\$
$\frac{7}{21} + 1 \frac{18}{21} = 2 \frac{4}{21} \\ \\ 2 \frac{4}{21}= 2 \frac{4}{21}$