Bài làm:

Ta có: \(3^{15}-9^6\)

\(=3^{15}-3^{12}\)

\(=3^{12}\left(3^3-1\right)\)

\(=3^{12}.26=3^{12}.2.13⋮13\)

=> đpcm

không biết nữa

3¹⁵ - 9⁶

= 3¹⁵ - ( 3² )⁶

= 3¹⁵ - 3¹²

= 3¹²( 3³ - 1 )

= 3¹²( 27 - 1 )

= 3¹².26

= 3¹².2.13 chia hết cho 13 ( đpcm )

\(3^{15}-9^6=3^{15}-3^{12}=3^{12}\left(3^3-1\right)=3^{12}\cdot26\)

Vì: \(26⋮13\Rightarrow3^{12}\cdot26⋮13\Rightarrow3^{15}-9^6⋮13\)

--> Đpcm

\(3^{15}-9^6\)

\(=3^{15}-\left(3^2\right)^6\)

\(=3^{15}-3^{12}\)

\(=3^{12}.3^3-3^{12}.1\)

\(=3^{12}.27-3^{12}.1\)

\(=3^{12}\left(27-1\right)\)

\(=3^{12}.26\)

\(=3^{12}.2.13⋮13\Rightarrowđpcm\)

Ta có: \(3^3\equiv1\left(mod13\right)\)

\(\Rightarrow3^{15}\equiv1\left(mod13\right)\)

\(9^3\equiv1\left(mod13\right)\)

\(\Rightarrow9^6\equiv1\left(mod13\right)\)

\(\Rightarrow3^{15}-9^6\equiv0\left(mod13\right)\)

\(\Rightarrow3^{15}-9^6⋮13\)

\(\Rightarrowđpcm\)

\(3^{15}-9^6=3^{15}-\left(3^2\right)^6=3^{15}-3^{12}=3^{12}.27-3^{12}.1=3^{12}.\left(27-1\right)=3^{12}.2.13\)Chia hết cho 13

Ta có : 3^15 - 9^6 = 3^15 - (3^2)^6

                           = 3^15 - 3^12

                           =  3^12 x (3^3 - 1)

                           = 3^12 x 26

Do 26 chia hết cho 13 nên 3^12 x 26 chia hết cho 13 hay 3^15 - 9^6 chia hết cho 13

đề bài sai rùi bn ơi

\(3^{15}-9^6=3^{15}-\left(3^2\right)^6=3^{15}-3^{12}=3^{12}\left(3^3-1\right)=3^{12}\cdot26=3^{12}\cdot13\cdot2⋮13\)

giải bằng phép đồng dư giúp mk