\overline{abc}-\overline{cba}=100a+10b+c-(100c+10b+a)=100a+10b+c-100c-10b-a=(100a-a)-(100c-c)+(10b-10b)=99a-99c+0=99a-99c=99(a-c)=9.11.(a-c)\vdots 11 AA a;c=>\overline{abc}-\overline{cba}\vdots 11(đpcm)Vậy \overline{abc}-\overline{cba}\vdots 11 Trả lời
Giả sử : a=5;b=4;c=3 =>543-345=198 Mà 198=11.18 =>198vdots11 =>overline(abc)-overline(cba)vdots11 (đpcm) Trả lời
=100a+10b+c-(100c+10b+a)
=100a+10b+c-100c-10b-a
=(100a-a)-(100c-c)+(10b-10b)
=99a-99c+0
=99a-99c
=99(a-c)=9.11.(a-c)\vdots 11 AA a;c
=>\overline{abc}-\overline{cba}\vdots 11(đpcm)
Vậy \overline{abc}-\overline{cba}\vdots 11