Răspuns:
2+x+9+x= k care trebuie sa fie un numar divizibil cu 3
2+x+9+x= 12,15,18,21,24,27
2+x+9+x=12=> 2091, 2190
2+x+9+x=15=>2193,2292,2391
2+x+9+x=18=>2196,2295,2394,2493,2592,2691
2+x+9+x=21=>2298,2397,2496,2595,2694,2793,2892
2+x+9+x=24=>2499,2598,2697,2796,2895,2994
2+x+9+x=27=>2799,2898,2997
Explicație pas cu pas:
