Câu hỏi của ❖ Khang/GD❄ 『ʈєɑɱ❖Hoàng...

Question

Cho 10K - 1 ⋮ 19 ( K>1 ) chứng tỏ102K - 1 ⋮ 19103K - 1 ⋮ 19

Nguyễn Lê Phước Thịnh · Accepted Answer

$10^{2k}-1=\left(10^k-1\right)\left(10^k+1\right)⋮19$Câu trả lời: $10^{2k}-1=\left(10^k-1\right)\left(10^k+1\right)⋮19$

Nguyễn Hoàng Minh · Answer

$10^{3k}-1=\left(10^k-1\right)\left(10^{2k}+10^k+1\right)⋮19$Câu trả lời: $10^{3k}-1=\left(10^k-1\right)\left(10^{2k}+10^k+1\right)⋮19$