6x + 5 >= 136x >= 13 - 56x >= 8x >= 8/6x >= 4/3
28 - 4x > 20-4x > 20 - 28-4x > -8x < 2
Ответ: x >= 4/3 и x < 2
6x + 5 >= 13
6x >= 13 - 5
6x >= 8
x >= 8/6
x >= 4/3
28 - 4x > 20
-4x > 20 - 28
-4x > -8
x < 2
Ответ: x >= 4/3 и x < 2