Answer:
21. |x - 5| < 20
x - 5 < 20
x < 25
-(x - 5) < 20
-x + 5 < 20
-x < 15
x > -15
22. |x + 4| > 13
x + 4 > 13
x > 9
-(x + 4) > 13
-x - 4 > 13
-x > 17
x < -17 or x > 9
