ab x 101 = ab x ( 100 + 1 ) 

= ab x 100 + ab x 1

= ab00 + ab

= abab

b ) abc x 7 x 11 x 13 = abc x 1001

abc x ( 1000 + 1 )

= abc x 1000 + ab x 1

= abc000 + abc = abcabc

ab x 101 = ab x ( 100 + 1 ) 

= ab x 100 + ab x 1

= ab00 + ab

= abab

b ) abc x 7 x 11 x 13 = abc x 1001

abc x ( 1000 + 1 )

= abc x 1000 + ab x 1

= abc000 + abc = abcabc

cảm ơn nha

a/ ab.101 = abab

b/ abc.7.11.13

=abc . 1001

= abcabc.

a. ab.101=abab

b. abc.7.11.13=abc.1001=abcabc

abc.7.11.13 = abc.1001 = abc(1000 + 1)

= abc.1000 + abc = abc000 + abc = abcabc

ab.101=abab

abc.7.11.13=abc.1001=abcabc

a)=abab

b)abcabc

thanks bạn đẹp traii nha 

Tr...bn đz nào ở đây

Tui là gái....ai ns vs bn tui là trai chớ...hic...

a) \(\overline{ab}.101=\overline{ab}.\left(100+1\right)\)

\(=\overline{ab}.100+\overline{ab}\)

\(=\overline{ab00}+\overline{ab}\)

\(=\overline{abab}\)

b) \(\overline{abc}.7.11.13=\overline{ab}.1001\)

\(=\overline{ab}.\left(1000+1\right)\)

\(=\overline{ab}.1000+\overline{ab}\)

\(=\overline{ab000}+\overline{ab}\)

\(=\overline{ab0ab}\)

a) abab

b) abcabc