Question

chứng minh rằng 

\(\overline{ba}+\overline{ab}⋮11\)

Answer 1

Ta có :

\(\overline{ab}+\overline{ba}\)

\(=\left(10a+b\right)+\left(10b+a\right)\)

\(=11a+11b\)

\(=11.\left(a+b\right)⋮11\)

Answer 2

Giải:

Ta có:

\(\overline{ba}+\overline{ab}=10b+a+10a+b=11b+11a=11\left(a+b\right)⋮11\)

Vậy \(\overline{ba}+\overline{ab}⋮11\) (Đpcm)