Question

Chứng minh rằng:

a) 7^6+7^5-7^4 chia hết cho 55 ;

b) 16^5+2^15 chia hết cho 33;

c) 6^300+6^299+6^298 chia hết cho 43;

d)5^2001+5^2000+5^1999 chia hết cho 155

Answer 1

a,=7^4(7^2+7-1)

=7^4.55 vậy nó chia hết cho 55

b,16^5=2^20

2^15(2^5+1)

2^15.33 chia hết cho 33

các câu c,d cũng tương tự

Answer 2

deu chia het ca

Answer 3

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Answer 4

b) \(16^5+2^{15}⋮33\)

\(=\left(2^4\right)^5+2^{15}\)

\(=2^{20}+2^{15}\)

\(=2^{15}.\left(1+2^5\right)\)

\(=2^{15}.33⋮33\)