Chứng minh rằng 

a,5^5 - 5^4 + 5^3 chia het cho 7

7^6 : 7^5 - 7^4 chia het cho 11

10^6 - 5^7 chia het cho 59

10^9 + 10^8 10^7 chia het 22

3 + 2 +3 + 2 chia het cho 10 n thuoc n*

1) Thuc hien phep tinh:

a) 4^6 × 9^2 / 6^3 × 8^2

b) 5^6 × 15^4 /5^4 × 3^3

c) 3^9 - 2^3 × 3^7 + 2^10 × 3^2 - 2^13 / 3^10 - 2^2 × 3^7 + 2^10 × 3^3 - 2^12

d) (1/9)^10 : (1/3)^20

e) (1/64)^5 × (1/4)^7

2) Chung minh rang:

a)2014^100+2014^99 chia het cho 2015

b) 4^13+32^5-8^8 chia het cho 5

c) 81^27-27^9-9^13 chia het cho 405

Help me!! Pleass!!

Cho A= 1+2+2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^9+2^10+2^11. Chứng minh rằng A chia hết cho 9

chứng minh C chia hết cho 5

C=2^0+2^1+2x(2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^9+2^10)+2^11+2^12

Chứng minh rằng : (1+2+2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^9+2^10) chia hết cho 7

chung to rang :

a) 7.8.9.10 + 2.3.4.5.6 + 30 chia het cho 5

b) 2^3+2^4+2^5+2^6 chia het cho 3

c) 2^3+2^4+2^5+2^6 chia het cho 6

d) n.(n+215) chia het cho 2

e) (n+1).(n+2) chia het cho 2

g) 2016.n + 27 chia het cho 9

h)1.2.3+3.41+450 chia het cho 3

i) 3^3+3^4+3^5+3^6+3^7+3^8 chia het cho 4

k) 3^3+3^4+3^5+3^6+3^7+3^8 chia het cho 13

MONG CAC BAN GIUP MINH ,MINH RAT GAP!

[1+2+2^2+2^3+2^4+2^5+2^6+2^7] chia hết cho 3

[1+2+2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^9+2^10+2^11] chia hết cho 9

Chứng minh rằng:

a) 7^6 - 7^5 + 7^9 chia hết cho 11

b) 10^9 + 10^8 +10^7 chia hết cho 22

c) 81^7 - 27^9 - 9^13 chia hết cho 45

d) 3^n+2 - 2^n+2 + 3^n - 2^n chia hết cho 45

Chứng minh rằng 

a.5^1 - 5^9 + 5^8 chia hết cho 7

b.6 + 6^2 + 6^3 + 6^4 + .........+ 6^9 + 6^10 chia hết cho 7

c.1+2+3+3^2+3^3+....+3^99 chia hết cho 4