289=Impartitor*25 +rest
rest≥1
rest=1
288=impartitor*25 Imp∉N
rest=2
287= Im*25
....
rest=4
285=Imp *25 Imp∉N
...........
rest=9
280=Imp *25 Imp∉N
rest=14
275=Imp *25 Imp=11nu conviner, pt ca rest 14>impartitor 11
rapuns problema nu are solutie in N
ALTFEL;
289:11=26 rest 3
289:12=24 rest 1
nu exista n∈N asa fel incat 289:n=cat 25, rest oricat
S=∅