-4/x+1 ∈ Z ⇒ x+1∈[tex]D_4[/tex]
x+1 ∈ {-1,1,-2,2,-4,4}/-1
x∈{-2,0,-3,1,-5,3}
______________________
-7/2x+1 ∈ Z ⇒ 2x+1 ∈ [tex]D_7[/tex]
2x+1 ∈ {-1,1,-7,7}/-1
2x ∈ {-2,0,-8,6}/:2
x ∈ {-1,0,-4,-3}
______________________
2x+1/x+2 ∈ Z ⇒ x+2|2x+1
x+2|2x+1⇒x+2|2(x+2)
x+2|x+2⇒x+2|2x+4
x+2|2x+4-2x-1⇒x+2|3⇒x+2∈
[tex]D_3[/tex]
x+2∈{-1,1,-3,3}/-2 ⇒ x∈{-3,-1,-5,1}
