Question

chứng minh rằng:

\(8^7-2^{18}\) chia hết cho 14

Answer 1

\(8^7-\left(2^3\right)^6=8^7-8^6=8^6\left(8-1\right)\)

Vì 8^6 chia hết cho 2

Nên 8^6.7 chia hết cho 14

Answer 2

\(8^7-2^{18}=\left(2^3\right)^7-2^{18}=2^{21}-2^{18}=2^{18}\left(2^3-1\right)=2^{17}.2.7\)

Chia hết cho 14

Answer 3

Ta có: \(8^7=\left(2^3\right)^7\)

=> 8⁷ - 2¹⁸ = (2³)⁷ - 2¹⁸ = 2²¹ - 2¹⁸ = 2¹⁸ . (2³ - 1 ) = 2¹⁸ . 7 = 2¹⁷ . 2 . 7  = 2¹⁷ .14 chia hết cho 14 (đpcm)

Ai k mik mik k lại

Answer 4

8⁷=(2³)⁷=2²¹

ta có: 2²¹-2¹⁸=2¹⁷x2x(2³-1)=2¹⁷x2x7 chia hết cho 14

Answer 5

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