Question

Chứng minh rằng ab+ba chia hết cho 11

Answer 1

Ta có: ab+ba =10a+b+10b+a =11a+11b =11(a+b) chia hết cho 11 Tick cho mình nha

Answer 2

Tick nha

Answer 3

ab+ba=10a+b+10b+a

=11a+11b

=11(a+b) \(⋮\) 11

Answer 4

ab+ba

=a.10+b.1+b.10+a.1

=a.10+a.1+b.10+b.1

=a.(10+1)+b.(10.1)

=a.11+b.11

=11.(a+b)\(⋮\)11(vì 11\(⋮\)11)

Answer 5

ab+ba=a.10+b+b.10+a=a.(10+1)+b.(10+1)

=a.11+b.11=11.(a+b)\(⋮\)11

Answer 6

a)ab+ba

Ta có:ab=10a+b

          ba=10b+a

 ab+ba=10a+b+10b+a

           =  11a  + 11b

Ta thấy: 11a⋮11   ;   11b⋮11

=>ab+ba⋮11 (ĐPCM)