So, for values lesser than -1 and greater than -7 this inequality is true.
In this inequality let's work applying the Absolute Value properties
1) -5ln+4l<15 Dividing both sides by 5
-|n+4|<3
|n+4|>-3
2) Applying Absolute value properties
|n+4|>-3
|n+4|>-3
n+4-4>-4-3
n>-4-3
n>-7
|n+4|>3
n+4>3
n+4-4>3-4
n>-1
3) So n < -1 and >-7
So for values lesser than -1 and greater than -7 this inequality is true.