Răspuns :
abc=11(a+b+c)
100a+10b+c=11a+11b+11c
100a-11a=11b-10b+11c-c
89a=10c+b
89a=cb
=> a=1; cb=89; deci, b=9 si c=8
abc=198 b)
ABC = 11(A+B+C)
100×A+10×B+C = 11×A+11×B+11×C
100A-11×A = 11×B-10×B + 11×C - C
89×A = B+10×C
89×A = CB
Daca A = 1 => CB = 89, singura solutie.
=> A = 1, BC = 98 => ABC = 198