Question

Numerele intregi n pentru fractia 2n+6 / n+1 care apartine N
Orice nr real este solutie a inecuatiei (x- 1 /2)·(1/2-x)≤0

Answer 1

2n + 6 / n+1 apartine N daca si numai daca :
n+1 | 2n+6
Dar n+1 | n+1
=> n+1 | 2n+2
=> n+1 | 2n+6 - (2n+2)
n+1 | 4
=> n+1 apartine {-4,-2,-1,1,2,4}
=> n apartine {-5,-3,-2,0,1,3}