12 - 4x < 2x + 6
6 < 6x
1 < x
-2 ≤ 4x + 3 и 4x + 3 ≤ 11
-5 ≤ 4x и 4x ≤ 8
-5/4 ≤ x и x ≤ 2
-1.25 ≤ x ≤ 2
Ответ: a) x > 1; б) -1.25 ≤ x ≤ 2