a. 1/8=2ⁿ:16ⁿ

1/8=1/8ⁿ

=>n=1

b.27<3ⁿ<243

<=>3³<3ⁿ<3⁵

=>n=4

a) 1/8 . 16ⁿ = 2ⁿ

    1/8          = 2ⁿ : 16ⁿ

    1/8          = ( 2/16 )ⁿ

    1/8          = ( 1/8 )ⁿ

=> n = 1

b) 27 < 3ⁿ < 243

    3³ < 3ⁿ < 3⁵

=> n = 4

Bài làm:

a) \(\frac{1}{8}.16^n=2^n\)

\(\Leftrightarrow2^{4n}=2^{n+3}\)

\(\Rightarrow4n=n+3\)

\(\Rightarrow3n=3\)

\(\Rightarrow n=1\)

Vậy n=1

b) \(27< 3^n< 243\)

\(\Leftrightarrow3^3< 3^n< 3^5\)

\(\Rightarrow3< n< 5\)

\(\Rightarrow n=4\)

Vậy n=4

Học tốt!!!!

mk chắc chắn 100% là n >1

b)\(27< 3^n< 243\)

\(3^3< 3^n< 3^5\)

\(\Rightarrow3< n< 5\)

\(\Rightarrow n\in\left\{4\right\}\)

a)\(\frac{1}{8}.16^n=2^n\)

\(\frac{16^n}{8}=2^n\)

\(\Rightarrow\frac{2^{4n}}{2^3}=2^n\)

\(\Rightarrow2^{4n-3}=2^n\)

\(\Rightarrow4n-3=n\)

\(\Rightarrow n=1\)

ok con de

23

Bạn ghi cách làm luôn hộ mk

a=1

b=4

27 < 3ⁿ < 243

=> 3³ < 3ⁿ < 5

=> 3 < n < 5 

=> n = 4

\(3^3< 3^n< 3^5\)
\(3< n< 5\)
Vậy n= 4

    27 < 3ⁿ < 243

=>3³ < 3 ⁿ < 3⁵

=> 3 < n < 5 

=> n = 4

Vậy n = 4 

a/ \(\frac{1}{8}.16^n=2^n\)

=> \(\frac{1}{8}.2^{4n}=2^n\)

=> \(\frac{2^n}{2^{4n}}=\frac{1}{8}\)

=> \(2^{n-4n}=2^{-3}\)

=> \(n-4n=-3\)

=> \(n=1\)

b/ 27 < 3ⁿ <243

hay 3³ < 3ⁿ < 3⁵

=> 3< n <5

=> n = 4