33 = 3.11

54 = 2.3^3

BCNN(33; 54) = 2.11.3^3 = 594

BC(33; 54) = B(594) = {0; 594; 1188;...}

A = 7^3 + 7^4 + 7^5 + ... + 7^100

St1 = 7\(^{1+2}\)

St2 = 7\(^{2+2}\)

St3 = 7\(^{3+2}\)

........

Stn = 7\(^{n+2}\)

A = 7^3 + 7^4 + 7^5 + ... + 7^100

St1 = 7\(^{1+2}\)

St2 = 7\(^{2+2}\)

St3 = 7\(^{3+2}\)

........

Stn = 7\(^{n+2}\)

C = 3\(^3\) + 3\(^6\) + 3\(^9\) + ... + 3\(^{21}\)

ST1 = 3\(^{1.3}\)

ST2 = 3\(^{2.3}\)

St3 = \(3^{3.3}\)

..................

St\(^{n}\) = 3\(^{n.3}\)

a. 84 : 4 + 3⁹ : 3⁷ + 5⁰

= 21 + 3² + 1

= 21 + 9 + 1

= 21 + 10 = 31

b. 2010 - 2000 : [ 486 - 2.(7² - 6) ]

= 2010 - 2000 : [ 486 - 2.(49 - 6) ]

= 2010 - 2000 : ( 486 - 2.43 )

= 2010 - 2000 : ( 486 - 86 )

= 2010 - 2000 : 400

= 2010 - 5

= 2005

c. 6² - 120 + (-5) - |-5|

= 36 - 120 - 5 - 5

= 36 - 

a; A = 7^2007-5.7^2005+4.7^2004 chia hết cho 13

A = 7^2004.(7^3 - 5.7 + 4)

A = 7^2004.(343 - 35 + 4)

A = 7^2004.(298 + 4)

A = 7^2004.312

A = 7^2004.13.24

Vì 13 chia hết cho 13 nên A chia hết cho 13 đpcm

Câu 2:Tìm số nguyên x,biết:

a/x-3 chia hết cho 3x-2

Giải

(x - 3) ⋮ (3x - 2)

(3x - 9) ⋮ (3x - 2)

(3x - 2 - 7) ⋮ (3x - 2)

7 ⋮ (3x - 2)

(3x - 2) ∈ Ư(7) = {-7; -1; 1; 7}

\(x\in\) {-5/3; 1/3; 1; 3}

Vì \(x\in\) Z nên \(x\) ∈ {1; 3}

Vậy \(x\) ∈ {1; 3}

3^3.3^4 = 3^12 (S) 9^12 S; 3^7 Đ 6^6 S

vì 3^3.3^4 = 3^(3 + 4) = 3^7

5^5 : 5 = 5^5(S); 5^4 Đ; 5^3 S

Vì 5^5 : 5 = 5^(5 - 1) = 5^4

a)9^5:3^7=27

b)4^7:2^7=128

c)2^5:4^7= ko có kết quả

d)5^4:125=5

e)8^5:4^7=2

g)8^3:4^4=2

nhớ **** cho mình nha

a) 9⁵:3⁷=(3²)⁵:3⁷=3¹⁰:3⁷=3³=27

b)4⁷:2⁷=(4:2)⁷=2⁷

c)2⁵:4⁷=2⁵:(2²)⁷=2⁵:2¹⁴=2^-9

d)5⁴:125=5⁴:5³=5

e)8⁵:4⁷=2⁵x4⁵:4⁷=2⁵x(2²)^-2=2⁵x(2)^-4=2

g)8³:4⁴=2³x4³:4⁴=2³x(2²)^-1=2³x(2)^-2=2

a) \(\left(3^5\times3^7\right):3^{10}+5\times2^4-7^3:7=3^{12}:3^{10}+5\times2^4-7^2\)

\(=3^2-5\times16-7^2=9-80-49=-120\)

b) \(15:\left(3^5:3^4\right)-2^9:2^7=15:3-2^2=5-4=1\)

c)\(5\times3^5:\left(3^8:3^5\right)-2^3\times5=5\times3^5:3^3-2^3\times5\)

\(=5\times3^2-2^3\times5=5\times9-8\times5=45-40=5\)