Ta có: \(8^7-2^{18}\)

\(=\left(2^3\right)^7-2^{18}\)

\(=2^{21}-2^{18}\)

\(=2^{18}.\left(2^3-1\right)\)

\(=2^{18}.7\)

\(=2^{17}.2.7\)

\(=2^{17}.14\)

Vì \(14⋮14\) nên \(2^7.14⋮14.\)

=> \(8^7-2^{18}⋮14\left(đpcm\right).\)

Chúc bạn học tốt!

*Ta có : 8⁷ - 2¹⁸

= (2³)⁷ - 2¹⁸

= 2²¹ - 2¹⁸

= 2¹⁸ . ( 8 - 1)

= 2¹⁷ . 2 . 7

= 2¹⁷ . 14 \(⋮\) 14

*Hay : 8⁷ - 2¹⁸ \(⋮\) 14. (đpcm)

*Tick nhé bạn!

Ta có: 8⁷-2¹⁸=1835008

- 1835008 chia hết cho 14 <=> 1835008 chia hết cho 7 và 2

mà 1835008: 7=262144

     1835008: 2=917504

=> 8⁷-2¹⁸ chia hết cho 14.

a) 8⁷-2¹⁸

=(2³)⁷-2¹⁸

=2²¹-2¹⁸

=2¹⁸.(2³-1)

=2¹⁸. 7

=2¹⁷.2.7

=2¹⁷.14  chia het cho 14

81^7-27^9-9^13 
=(3^4)^7-(3^3)^9-(3^2)^13 
=3^28-3^27-3^26 
=(3^26.3^2)-(3^26.3^1)-(3^26.1) 
=3^26.(9-3-1) 
=3^22.(3^4.5) 
=3^22.405 chia het cho 405 
=> 81^7-27^9-9^13 chia het cho 405

a.

8⁷ - 2¹⁸ = (2³)⁷ - 2¹⁸ = 2²¹ - 2¹⁸ = 2¹⁷ x (2⁴ - 2) = 2¹⁷ x (16 - 2) = 2¹⁷ x 14

Vậy 8⁷ - 2¹⁸ chia hết cho 14.

b.

81⁷ - 27⁹ - 9¹³ = (3⁴)⁷ - (3³)⁹ - (3²)¹³ = 3²⁸ - 3²⁷ - 3²⁶ = 3²² x (3⁶ - 3⁵ - 3⁴) = 3²² x 405

Vậy 81⁷ - 27⁹ - 9¹³ chia hết cho 405

\(8^7-2^{18}=\left(2^3\right)^7-2^{18}=2^{21}-2^{18}=2^{17}\left(2^4-2\right)=2^{17}.14⋮14\)

\(8^7-2^{18}\)

\(=2^{21}-2^{18}\)

\(=2^{18}\left(2^3-1\right)=2^{18}.7\)

\(=2^{17}.14⋮14\)

8^7 - 2^18 

=(2^3)^7-2^18

=2^21-2^18

=2^18.2^3-2^18.1

=2^18.8-2^18.1

=2^18.(8-1)

=2^18.7

=2^17.2^1.7

=2^17.2.7

=2^17.(2.7)

=2^17.14 chia hết cho 14

Ta có :

\(8^7-2^{18}\)

\(=\left(2^3\right)^7-2^{18}\)

\(=2^{21}-2^{18}\)

\(=2^{18}\left(2^3-1\right)\)

\(=2^{18}.7\)

\(=2^{17}.14⋮14\)

\(\Leftrightarrow8^7-2^{18}⋮14\left(đpcm\right)\)

Ta có: 8⁷-2¹⁸=(2³)⁷-2¹⁸

                  =2²¹-2¹⁸

                  =2¹⁷(2⁴-2)

                 =2¹⁷.14 chia hết cho 14 (đpcm)

???
 

8⁷-2¹⁸ chia hết cho 14

Ta có:8⁷-2¹⁸ =8³.8⁴ -2⁹.2⁹=512.4096-512.512 =512.(4096-512)=512.3584

Vì 3584 chia hết cho 14 nên 512.3584 chia hết ch 14 hay 8⁷-2¹⁸ chia hết cho 14 (đpcm)

chúc bạn học tốt

Ta có: \(8^7-2^{18}\)

\(=\left(2^3\right)^7-2^{18}\)

\(=2^{21}-2^{18}\)

\(=2^{17+4}-2^{17+1}\)

\(=2^{17}.2^4-2^{17}.2\)

\(=2^{17}\left(2^4-2\right)\)

\(=2^{17}.14⋮14\)

Vậy \(\left(8^7-2^{18}\right)⋮14\)

Chúc bạn học tốt

\(8^7-2^{18}\\ =\left(2^3\right)^7-2^{18}\\ =2^{21}-2^{18}\\ =2^{17}\cdot\left(2^4-2\right)\\ =2^{17}\cdot14⋮14\)

Vậy \(8^7-2^{18}⋮14\)

\(8^7-2^{18}\)

\(=\left(2^3\right)^7-2^{18}\)

\(=2^{21}-2^{18}\)

\(=2^{18}.2^3-2^{18}.1\)

\(=2^{18}.8-2^{18}.1\)

\(=2^{18}\left(8-1\right)\)

\(=2^{18}.7\)

\(=2^{17}.14⋮14\)

\(\rightarrowđpcm\)

8⁷-2¹⁸=(2³)⁷-2¹⁸=2²¹-2¹⁸=2¹⁸.(2³-1)=2¹⁸.7 = 2¹⁷​.14 chia hết cho 14