Under the absolute value could be positive or negative number, but absolute value make them both positive.
For positive number we can write is (4x+3) and for negative -(4x+3)
4x+3<9
4x< 6
x< 3/2 (-∞, 3/2)
-(4x+3)<9
-4x-12<9
-4x<21
x>-21/4 (-21/4, +∞)
(-∞, 3/2)∩ (-21/4, +∞) =(-21/4, 3/2) it could be written as (-5.25, 1.5)
