a) Sai

b) Sai

c) Đúng

a sai

b sai

c đúng

Bài 1: Tính bằng 2 cách:

a) 2^5 : 2^4

= 2

b) 3^4 : 3^2

= 3

c) 6^3 : 6^2

= 6

d) 8^4 : 8^2

= 8^2

= 64

e) 7^5 : 7^4

= 7

f) 100^3 : 100

= 100^2

= 10000

Bài 2: Tìm số tự nhiên x, biết:

a) 2^x = 16

2^x = 2^4

x = 4

Vậy x = 4

b) 3^x = 243

3^x = 3^5

x = 5

Vậy x = 5

c) 5^x+1 = 125

5^x + 1 = 5^3

x + 1 = 3

x = 3 - 1

x = 2

Vậy x = 2

a) 4.5²-3.2³ = 2².5²-3.2³ = 2².(5²-3.2) =2².(25-6) = 4.19 = 76

b) 28.76 + 13.28 + 9.2

= 28. (76 + 13) + 18

= 28. 89 + 18

= 2492 + 18

= 2510

c) 1024: ( 17 .2⁵+15.2⁵)

= 2¹⁰ : [2⁵.(17+15)]

= 2¹⁰: [2⁵. 32]

= 2¹⁰: [2⁵.2⁵)

= 2¹⁰:2¹⁰

= 1

a) 4.5²-3.2³

=2².5²-3.2³

=2².(25-6)

=4.11

=44
 b) 28.76+13.28+9.2

=28.(76+13)+9.2

=28.89+9.2

=2.(1246+9)

=2.1255

=2510
 c) 1024:(17.2⁵+15.2⁵)

=1024:2⁵.(17+15)

=1024:32.32

=1

a)  27^16 : 9^10

Ta có: (3.9)^16 : 9^10

        = 3^16.9^16: 9^10

        = 3^16. 9^6

        = 3^16.(3^2)^6

       =3^16.3^12

       =3^28

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}

Dài thế

giúp tớ  những cau cau biết nhé

Ta có : 

\(A=\frac{8^{24}.1215}{2^5.432}\)

\(\Rightarrow A=\frac{\left(2^3\right)^{24}.\left(3^5.5\right)}{2^5.\left(2^4.3^3\right)}\)

\(\Rightarrow A=\frac{2^{72}.3^5.5}{2^5.2^4.3^3}\)

\(\Rightarrow A=\frac{2^{72}.3^5.5}{2^9.3^3}\)

\(\Rightarrow A=\frac{2^{63}.3^2.5}{1.1}\)

\(\Rightarrow A=2^{63}.9.5\)

\(\Rightarrow A=2^{63}.45\)

Vậy \(A=2^{63}.45\)

~ Ủng hộ nhé 

Ta có : 

\(B=\frac{15^5.12^{10}}{6^8.9^3}\)

\(\Rightarrow B=\frac{\left(3.5\right)^5.\left(2^2.3\right)^{10}}{\left(2.3\right)^8.\left(3^2\right)^3}\)

\(\Rightarrow B=\frac{3^5.5^5.\left(2^2\right)^{10}.3^{10}}{2^8.3^8.3^6}\)

\(\Rightarrow B=\frac{3^{15}.5^5.2^{20}}{2^8.3^{14}}\)

\(\Rightarrow B=\frac{3.3125.2^{12}}{1.1}\)

\(\Rightarrow B=3.3125.4096\)

\(\Rightarrow B=38400000\)

Vậy \(B=38400000\)

a) \(5.\left(x-3\right)=15\)

\(x-3=15:5\)

\(x-3=3\)

\(x=6\)

b)\(10+2.x=4^5:4^3\)

\(10+2.x=16\)

\(2x=16-10\)

\(2x=6\)

\(x=3\)

c) \(5^{x+1}=125\)

\(5^{x+1}=5^3\)

\(x+1=3\)

\(x=2\)

d) \(5^{2x-3}-2.5^2=5^2.3\)

\(5^{2x-3}=2.5^2+5^2.3\)

\(5^{2x-3}=125\)

\(5^{2x-3}=5^2\)

\(2x-3=2\)

\(2x=6\)

\(x=3\)

Mk nhanh nek bn

Đúng k bn