Question

Cate numere indeplinesc conditia
$\frac{25}{2x + 1}$
apartine N ?

a) 2
b) 3
c) niciunul

Answer 1

25/(2x+1)  ∈N => 2x+1∈D25
2x+1={1,5,25}
2x+1=1 =>x=0
2x+1=5 =>x=2
2x+1=25 =>x=12
x={0,2,12}

R: 3 numere;  b)