Question

5 supra 12 < 2n supra 26 < 6 supra 9

Answer 1

5/12 < 2n/26 < 6/9        aducem la acelasi numitor

5*39 < 2n * 18 < 6*52  |:2

2,5 * 39 < 18n < 3 *52  

97,5 < 18n < 156   |:18

5,41 < n < 8,66   => n=(5,41; 8,66)  

daca n este numar natural n={6,7,8}