Question

n=? daca
12/ 2n+1 ∈ Z ?

Answer 1

2n+1 apartine divizorilor lui 12
2n+1 apartine {-1,1,-2,2,-3,3,-4,4,6,-6,-12,12}
2n+1=-1  2n=-2  n=-1
2n+1=1   2n=0  n=0
2n+1=-2   2n=-3   n=-3/2 nu apartine la Z
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2n+1=12  2n=11 n=11/2 nu apartine la Z
n apartine {-2,-1,0,1}