-14 < x < 13
14 < x < -13
-13 < x < 14
-14 < x < - 13
Correct answer is A
12x2 < x + 1
12 - x - 1 < 0
12x2 - 4x + 3x - 1 < 0
4x(3x - 1) + (3x - 1) < 0
Case 1 (+, -)
4x + 1 > 0, 3x - 1 < 0
x > -14x < 13
Case 2 (-, +) 4x + 1 < 0, 3x - 1 > 0
-14 < x < - 13