\(a,2^x.4=128\\2^x.2^2=2^7\\ 2^x=\dfrac{2^7}{2^2}=2^{7-2}=2^5\\ Vậy:x=5\\ ----\\ b,\left(2x+1\right)^3=125=5^3\\ \Rightarrow 2x+1=5\\ 2x=5-1=4\\ x=\dfrac{4}{2}=2\\ ----\\ c,2x-2^6=6\\ 2x=6+2^6=6+64\\ 2x=70\\ x=\dfrac{70}{2}=35\\ ----\\ d,49.7^x=2401\\ 7^x=\dfrac{2401}{49}=49=7^2\\ Vậy:x=2\)

 a) 5^3 = 125

b)3^4.3^3=3^7

c)27.3^2=243

d)49.7^2=2401

e) chịu -_-

+/\(2^n=32\)(=) \(2^n=2^5\)

=> \(n=5\)

+/\(64.4^n=4^5\) (=) \(4^3.4^n=4^5\)

(=)\(4^n=4^2\) => \(n=2\)

 Các ý còn lại bạn tự làm nhé !!

2^5 = 32

64*4^2=4^5

27*3^2=243

49*7^2=2401

9<3^3<81

Đây là tìm n nhé bn

b) Ta có :

n³⁵ : n³² = 64

n³ = 64

4³ = 64

=> n = 4

\(b,\text{ }n^{35}\text{ : }n^{32}=64\)

\(n^3=64\)

\(n^3=4^3\)

\(\Rightarrow\text{ }n=4\)

\(c,\text{ }49\cdot7^{2n+3}=2401\cdot343\)

\(7^2\cdot7^{2n+3}=7^4\cdot7^3\)

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

\(7^{2n+5}=7^7\)

\(\Rightarrow\text{ }2n+5=7\)

\(2n=7-5\)

\(2n=2\)

\(n=2\text{ : }2\)

\(n=1\)

\(b,\text{ }n^{35}\text{ : }n^{32}=64\)

\(n^3=64\)

\(n^3=4^3\)

\(\Rightarrow\text{ }n=4\)

\(c,\text{ }49\cdot7^{2n+3}=2401\cdot343\)

\(7^2\cdot7^{2n+3}=7^4\cdot7^3\)

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

\(7^{2n+5}=7^7\)

\(\Rightarrow\text{ }2n+5=7\)

\(2n=7-5\)

\(2n=2\)

\(n=2\text{ : }2\)

\(n=1\)

Trả lời:

H.(7x-11)³ =2⁵.5² +200

=(7x-11)³ =32.25 +200    =(7x-11)³ =800 +200

=(7x-11)³ =1000               =(7x-11)³ = 10³ 

= 7x-11    = 10                  = 7x        = 10 + 11

= 7x         = 21                  =   x         = 21:7

= x           = 3

I.3^x +25   = 26.2²+2.3⁰

=3^x +25   = 26.4 +2.1        =3^x +25     = 106

=3^x            = 106-25          =3^x            = 81

=3^x               = 3⁴                  => x           =4

K.27.3^x= 243

= 3^x      =243:27

= 3^x      = 9

= 3^x      = 3²

=>  x     = 2

Mấy câu khác cứ thế làm nha

Cảm ơn bạn nha

Bài 3:

a) Ta có: \(2^x\cdot4=128\)

\(\Leftrightarrow2^x=32\)

hay x=5

Vậy: x=5

b) Ta có: \(2^x-26=6\)

\(\Leftrightarrow2^x=32\)

hay x=5

Vậy: x=5

c) Ta có: \(27\cdot3^x=3^7\)

\(\Leftrightarrow3^x=\frac{3^7}{27}=\frac{3^7}{3^3}=3^4\)

hay x=4

Vậy: x=4

d) Ta có: \(3^x=81\)

\(\Leftrightarrow3^x=3^4\)

hay x=4

Vậy: x=4

e) Ta có: \(64\cdot4^x=4^5\)

\(\Leftrightarrow4^3\cdot4^x=4^5\)

\(\Leftrightarrow4^{x+3}=4^5\)

\(\Leftrightarrow x+3=5\)

hay x=2

Vậy: x=2

g) Ta có: \(49\cdot7^x=2401\)

\(\Leftrightarrow7^2\cdot7^x=7^4\)

\(\Leftrightarrow7^{x+2}=7^4\)

\(\Leftrightarrow x+2=4\)

hay x=2

Vậy: x=2

h) Ta có: \(3^4\cdot3^x=3^7\)

\(\Leftrightarrow3^{x+4}=3^7\)

\(\Leftrightarrow x+4=7\)

hay x=3

Vậy: x=3

a. n = 4

A. 3^n=3^4

        n=4

b.5^n=125

   5^n=5^3

      n=3

a,\(3^n\)=81

3^n = 3^4

=> n = 4

b,5^n=125

5^n = 125

5^n = 5^3

=> n = 3

c,2^3.2^4=64

Sai đề nhé!

d,7.7^n+1=343

7.7^n+1 = 7^3

7^n+1 = 7^3:7 

7^n+1 = 7^2

n+1 = 2 => n = 1

e,2.3^n=162

3^n = 162:2

3^n = 3^4

=> n = 4

g,49.7^n=2401

7^2.7^n = 7^4

7^n = 7^4:7^2

7^n = 7^2 => n= 2

\(a.64.4^x=16^8=>x=13\)

b.\(49.7^x=2401=>x=2\)

\(c.27.3^x=243=>x=2\)

\(e.3^5=243=>x=5\)

\(â,64.4^x=16^8\)

Trả lời:

a)64.4^x=16⁸

4³.4^x=4¹⁶

4^x=4¹⁶:4³

4^x=4¹³

\(\Rightarrow\)x=13

Vậy x=13

b)49.7^x=2401

7².7^x=7⁴

7^x=7⁴:7²

7^x=7²

\(\Rightarrow\)x=2

Vậy x=2

c)27.3^x=243

3³.3^x=3⁵

3^x=3⁵:3³

3^x=3²

\(\Rightarrow\)x=2

Vậy x=2

e)3^x=243

3^x=3⁵

\(\Rightarrow\)x=5

Vậy x=5

a N = 5

 b N = 2

c N = 2

d N = 2

tk minh nha

2ⁿ = 32

=> 2ⁿ = 2⁵

=> n = 5

27.3ⁿ = 243

3ⁿ = 243 : 27

3ⁿ = 9

3ⁿ = 3²

=> n = 2

64.4ⁿ = 4⁵

64.4ⁿ = 1024

4ⁿ = 1024 : 64

4ⁿ = 16

4ⁿ = 4²

=> n = 2

49.7ⁿ = 2401

7ⁿ = 2401 : 49

7ⁿ = 49

7ⁿ = 7²

=> n = 2