x+2/x+11 => x ∈ R \ {-11}
x+11 | x+11
x+11 | x+2
x+11 | (x+2)-(x+11)
x+11 | -9
x+11 | D9
D9 = ±1 ; ±3 ; ±9
x₁+11 = -1 => x₁ = -12
x₂+11 = 1 => x₂ = -10
x₃+11 = -3 => x₃ = -14
x₄+11 = 3 => x₄ = -8
x₅+11 = -9 => x₅ = -20
x₆+11 = 9 => x₆ = -2
=> x ∈ {-20 ; -14 ; -12 ; -10 ; -8 ; -2}
