Question

C={x|x apartineN si 125este divizibil(2x+1)}

Answer 1

D125 ∈ {1,5,25,125}
2x + 1 = 1  x = 0
2x + 1 = 5    x = 2
2x + 1 = 25    x = 12
2x + 1 = 125    x = 62
C = {0,2,12,62}