Question

aflati nr nat x: 15x+5<10x+25

Answer 1

15x+5<10x+25
15x-10x<25-5
5x<20
x<20/5
x<4
x∈(-∞ ; 4)

Answer 2

15x+5<10x+25
15x-10x<25-5
5x<20
x<4,x={1,2,3}