Решите уравнение: 1) 1 / 3х + 1 / 5х + 1 / 6х = 21/40; 2) 1 / 4х + 1 / 6х + 1 / 8х = 39/56

ответ:

1) 1/3х + 1/5х + 1/6х = 21/40;
21/30х = 21/40;
х = 3/4;
2) 1/4х + 1/6х + 1/8х = 39/56;
13/24х = 39/56;
х = 9/7.