Răspuns :
a7b=b7a....=>a=b
171=171 ...=> 1*100+7*10+1=100+70+1=170+1=171
272=272......=> 2*100+7*10+2=200+70+2=270+2=272
373=373......=> 3*100+7*10+2=300+70+3=370+3=373
474=474
575=575
676=676
777=777
878=878
978=978
171=171 ...=> 1*100+7*10+1=100+70+1=170+1=171
272=272......=> 2*100+7*10+2=200+70+2=270+2=272
373=373......=> 3*100+7*10+2=300+70+3=370+3=373
474=474
575=575
676=676
777=777
878=878
978=978