Giải thích các bước giải:
Ta có:
\(\begin{array}{l}
a,\\
\overline {abcdeg} \\
= \overline {ab0000} + \overline {cd00} + \overline {eg} \\
= 10000.\overline {ab} + 100.\overline {cd} + \overline {eg} \\
= 9999.\overline {ab} + 99\overline {cd} + \left( {\overline {ab} + \overline {cd} + \overline {eg} } \right)\\
= 11.909.\overline {ab} + 11.9.\overline {cd} + \left( {\overline {ab} + \overline {cd} + \overline {eg} } \right)\\
= 11.\left( {909\overline {ab} + 9\overline {cd} } \right) + \left( {\overline {ab} + \overline {cd} + \overline {eg} } \right)\\
11.\left( {909\overline {ab} + 9\overline {cd} } \right)\,\, \vdots \,\,11\\
\left( {\overline {ab} + \overline {cd} + \overline {eg} } \right)\,\, \vdots \,\,11\\
\Rightarrow \left[ {11.\left( {909\overline {ab} + 9\overline {cd} } \right) + \left( {\overline {ab} + \overline {cd} + \overline {eg} } \right)} \right]\,\, \vdots \,\,11\\
\Rightarrow \overline {abcdeg} \,\, \vdots \,\,11\\
b,\\
\overline {abcdeg} \\
= \overline {abc000} + \overline {deg} \\
= 1000.\overline {abc} + \overline {deg} \\
= 999.\overline {abc} + \left( {\overline {abc} + \overline {deg} } \right)\\
= 37.27.\overline {abc} + \left( {\overline {abc} + \overline {deg} } \right)\\
\left( {37.27.\overline {abc} } \right)\,\, \vdots \,\,37\\
\left( {\overline {abc} + \overline {deg} } \right)\,\, \vdots \,\,37\\
\Rightarrow \left[ {37.27.\overline {abc} + \left( {\overline {abc} + \overline {deg} } \right)} \right]\,\, \vdots \,\,37\\
\Rightarrow \overline {abcdeg} \,\, \vdots 37
\end{array}\)
Đề câu 2 bị thiếu rồi em nhé!
