18а - 6b - 2a + 6b = 16a
---------------------------------
10 - 6x - 10 = 4x - 8
-6x - 4x = - 10 + 10 - 8
- 10x = - 8
x = 8/10 = 4/5
x = 4/5
1-17/42=42/42-17/42=25/42
1-1/100=100/100-1/100=99/100
Пусть n- количество ульев
( 8631- 7946)/n= 5кг
685=5n
n= 137 ульев