Ma puteti ajuta si pe mine cu exercitiul 8 ??

18/(x+2)∈N , daca x+2=D₁₈
D₁₈={1;2;3;6;9;18}
x+2=1=>x₁=-1
x+2=2=>x₂=0
x+2=3=>x₃=1
x+2=6=>x₄=4
x+2=9=>x₅=7
x+2=18=>x₆=16
S={±1,0,4,7,16}