Уравнение 8,31к-71=1,11к+1к

8,31к - 71 = 1,11к + 1к;

8,31к - 71 = 2,11к;

8,31к - 2,11к - 71 = 0;

6,2к - 71 = 0;

6,2к = 0 + 71;

6,2к = 71;

к = 71 : 6,2;

к = 71 : 62/10;

к = 71 * 10/62;

к = 355/31 = 11 14/31.

Проверка:

8,31 * 11 14/31 - 71 = 1,11 * 11 14/31 + 1 * 11 14/31;

8,31 * 355/31 - 71 = 1,11 * 355/31 + 1 * 355/31;

831/100 * 355/31 - 71 = 111/100 * 355/31 + 355/31;

831/20 * 71/31 - 71 = 111/20 * 71/31 + 355/31;

59001/620 - 71 = 7881/620 + 7100/620;

59001/620 - 44020/620 = 7881/620 + 7100/620;

14981/620 = 14981/620;

Ответ: к = 355/31 = 11 14/31.