Răspuns:
943
Explicație pas cu pas:
abc - scrierea zecimala a nr abc
abc=100a+10b+c
unde c=a-6
cba - scrierea zecimala a nr cba
cba=100(a-6)+10b+a=100a-600+10b+a=101a+10b-600
abc:cba=3rest 98
scriu teorema impartirii cu rest
abc=3xcba+98
100a+10b+a-6=3x[101a+10b-600]+98
100a+10b+a-6=303a+30b-1800+98
100a+10b+a=300a-1800+30b+3a+98
303a+30b-101a-10b-1800=98
202a+20b-1800=98
2(101a+10b-900)=2*49
101a+10b-900=49
101a+10b=949
a=9
909+10b=949
10b=40
b=4
c=3
