6. 1,5(2a + 2) + 2a < a + 2,9

1. 5(2a + 2) + 2a < a + 2.9
3a + 3 + 2a < a + 2.9
5a + 3 < a + 2.9
5a - a < 2.9 - 3
4a < -0.1
a < -0.1/4
a < -1/40
Ответ: a < -1/40