Ta có:

\(81^7-27^9-9^{13}\\ =\left(3^4\right)^7-\left(3^3\right)^3-\left(3^2\right)^{13}\\ =3^{28}-3^{27}-3^{26}\\ =3^{26}.\left(3^2-3-1\right)=3^{26}.5=3^{24}.3^2.5=3^{24}.45\)

Mà 45 ⋮ 45 nên \(3^{24}.45⋮45\)

\(\Rightarrow81^7-27^9-9^{13}⋮45\left(đcpcm\right)\)

+)We/go/circus/Sunday.

\(\Rightarrow\) We go to the circus on Sunday.

+)You/watch/T.V/evening?No

⇒ Do you watch TV in the evening? - No ( I don't ).

My English class starts ...\(at\)... ten minutes after three

Bạn có thể chụp lại đc không ạ

\(\overline{abcdeg}=1000.\overline{abc}+\overline{deg}\\ =1000.2.\overline{deg}+\overline{deg}\\ =\left(2000+1\right)\overline{deg}\\ =2001.\overline{deg}\\ =23.29.3.\overline{deg}⋮23,29\left(đcpcm\right)\)

Ta có:

+) \(2113^{2000}=\left(2113^4\right)^{500}=\left(\overline{...1}\right)^{500}\) ( Tận cùng là 1 ) \(\left(1\right)\)

+)\(2011^{2000}=2011.2011...2011=\overline{...1}\) ( Tận cùng là 1 ) \(\left(2\right)\)

Từ \(\left(1\right)\&\left(2\right)\)

 \(\Rightarrow2113^{2000}-2011^{2000}\\ =\overline{...1}-\overline{...1}\\ =\overline{...0}⋮2\&5\left(đcpcm\right)\)

1