4 2/9Х+3 5/14=6 11/21
38/9Х=137/21-3 5/14=137/21-47/14=274/42-141/42=133/42
Х=133/42:38/9=133/42х9/38=133/14х3/38
Х=399/532
проверка:
1 38/9 х 399/532=38/3 х 133/532=19/3х133/266=2527/798
2 2527/798+47/14=2527/798+2679/798=5206/798=6 418/798=6 209/399 (сокращаем на 19) = 6 11/21
6 11/21=6 11/21 верно
4 2/9Х+3 5/14=6 11/21
38/9Х=137/21-3 5/14=137/21-47/14=274/42-141/42=133/42
Х=133/42:38/9=133/42х9/38=133/14х3/38
Х=399/532
проверка:
1 38/9 х 399/532=38/3 х 133/532=19/3х133/266=2527/798
2 2527/798+47/14=2527/798+2679/798=5206/798=6 418/798=6 209/399 (сокращаем на 19) = 6 11/21
6 11/21=6 11/21 верно