(4/5-k)-1/3=1/6-1/10

(4/5 - k) - 1/3 = 1/6 - 1/10; (4/5 - k) - 1/3 = (1 * 5)/(6 * 5) - (1 * 3)/(10 * 3); (4/5 - k) - 1/3 = 5/30 - 3/30; (4/5 - k) - 1/3 = 2/30; (4/5 - k) = 2/30 + 1/3; (4/5 - k) = 2/30 + (1 * 10)/(3 * 10); (4/5 - k) = 2/30 + 10/30; (4/5 - k) = 12/30; к = 4/5 - 12/30; к = (4 * 6)/(5 * 6) - 12/30; к = 24/30 - 12/30; к = 12/30; к = 2/5. Проверка: (4/5 - 2/5) - 1/3 = 1/6 -1/10; 2/5 - 1/3 = (1 * 5)/(6 * 5) - (1 * 3)/(10 * 3); (2 * 3)/(5 * 3) - (1 * 5)/(3 * 5) = 5/30 - 3/30; 6/15 - 5/15 = 2/30; 1/15 = 2/30; 1/15 = 1/15. Решение выполнено верно.