Question

Aratati ca
ab + ba + ac + ca + bc + cb divizibil cu 11
(Totul ab......cu bara deasuprA)

Answer 1

Vom scrie toti termenii in forma zecimala si avem:
10a+b+10b+a+10a+c+10c+a+10b+c+10c+b=22a+22b+22c=11(2a+2b+2c)
Deci Suma este divizibila cu 11

Answer 2

$\overline{ab}+\overline{ba}+\overline{ac}+\overline{ca}+\overline{bc}+\overline{cb}=10a+b+10b+a+10a+c+10c+a+10b+c+10c+b=22a+22b+22c=11(2a+2b+2c)=\textgreater 11|\overline{ab}+\overline{ba}+\overline{ac}+\overline{ca}+\overline{bc}+\overline{cb}$