(1)
-4/5x>1
-1>4/5x
-5>4x
-5/4>x
(2)
5x<1+4x
5x-4x<1+4x-4x
x<1
(3)
2x+5<4x+1
2x+5-2x<4x+1-2x
5<2x+1
5-1<2x+1-1
4<2x
2<x