Question

chứng tỏ rằng :                        ( a , b khác 0 )

( abc abc + aba bab ) chia hết cho 7

Answer 1

\(\overline{abcabc}=100000a+10000b+1000c+100a+10b+c\)

\(=100100a+10010b+1001c\)

\(100100⋮7\Rightarrow100100a⋮7\)

\(10010⋮7\Rightarrow10010b⋮7\)

\(1001⋮7\Rightarrow1001c⋮7\)

\(\Rightarrow\overline{abcabc}⋮7\)

 \(\overline{ababab}=100000a+10000b+1000a+100b+10a+b\)

\(=101010a+10101b\)

\(101010⋮7\Rightarrow101010a⋮7\)

\(10101⋮7\Rightarrow10101b⋮7\)

\(\Rightarrow\overline{ababab}⋮7\)

vậy \(\left(\overline{abcabc}+\overline{ababab}\right)⋮7\left(đpcm\right)\)

Answer 2

abcabc+ababab chia het cho 7 vi 

minh chang hieu de

minh lop 2 nen ko tra loi duoc