mk đã làm r nhé bn

a)16/2ⁿ=2

=>16=2ⁿ.2

=>8=2ⁿ

=>2³=2ⁿ

=>n=3

b)(-3)ⁿ/81=-27

<=>(-3)ⁿ=(-27).81

<=>(-3)ⁿ=-2187

<=>(-3)ⁿ=(-3)⁷

<=>n=7

c)8ⁿ:2ⁿ=4

<=>8ⁿ=4.2ⁿ

<=>2³ⁿ=2²⁺ⁿ

<=>3n=2+n

<=>2n=2

<=>n=1

a) \(\frac{16}{2^n}=2\)

=> 2.2ⁿ = 16

=> 2¹⁺ⁿ = 2⁴

=> 1 + n = 4

=> n = 4 - 1

=> n = 3

Vậy n = 3

b) \(\frac{\left(-3\right)^n}{81}=-27\)

=> (-3)ⁿ = -27.81

=> (-3)ⁿ = -3³.3⁴

=> (-3)ⁿ = (-3)⁷

=> n = 7

Vậy n = 7

c) 8ⁿ : 2ⁿ = 4

=> (8 : 2)ⁿ = 4

=> 4ⁿ = 4¹

=> n = 1

Vậy n = 1

\(\frac{16}{2^n}=2\Rightarrow2^n=16:2\Rightarrow2^n=8\Rightarrow n=3\)

\(\frac{\left(-3\right)^n}{81}=-27\Rightarrow\left(-3\right)^n=\left(-27\right).81\Rightarrow\left(-3\right)^n=-2187\Rightarrow n=7\)

\(8^n:2^n=4\Rightarrow\left(8:2\right)^n=4\Rightarrow4^n=4\Rightarrow n=1\)

a) => 2ⁿ = 16/2 = 8

 => n = 3

b) => (-3)ⁿ  = -27 x 81 = -2187

 => n = 7

c) 8ⁿ : 2ⁿ = ( 8 : 2)ⁿ = 4ⁿ = 4

 => n = 1

a) \(\frac{16}{2^n}=2\)

\(2^4:2^n=2\)

\(2^n=2^4:2\)

\(2^n=2^3\)

vậy n=3

b;c làm tương tự

Bài làm sai rồi :

a) n=5

b) n=7

c) n=1

\(a,\frac{16}{2^n}=2\Rightarrow2^n=16:2\Rightarrow2^n=8\Rightarrow2^n=2^3\Rightarrow n=3\)

\(b,\frac{\left(-3\right)^n}{81}=-27\Rightarrow\left(-3\right)^n=81.\left(-27\right)\Rightarrow\left(-3\right)^n=-2187\Rightarrow3^n=3^7\Rightarrow n=7\)

\(c,8^n:2^n=4\Rightarrow4^n=4\Rightarrow n=1\)

\(a,\frac{16}{2^n}=2\)                                    \(b,\frac{\left(-3\right)^n}{81}=-27\)                                              \(c,8^n:2^n=4\)

\(\Rightarrow2^4=2^n.2\)                                 \(\Rightarrow\left(-3\right)^n=\left(-27\right).81\)                                \(\Rightarrow\left(8:2\right)^n=4\)

\(\Rightarrow4=n+1\)                                 \(\Rightarrow\left(-3\right)^n=\left(-3\right)^7\)                                        \(\Rightarrow4^n=4\)

\(\Rightarrow n=4-1=3\)                         \(\Rightarrow n=7\)                                                                \(\Rightarrow n=1\)

a)

b)

c)

a) $\frac{16}{2^n}=\mathrm{2\; =>\; \backslash (\backslash dfrac\{2^4\}\{2^n\}=2\backslash Rightarrow2^\{4-n\}=2\backslash Rightarrow4-n=1\backslash Rightarrow\; n=3\backslash )}$

b,
\(\dfrac{\left(-3\right)^n}{81}=-27\Rightarrow\dfrac{\left(-3\right)^n}{\left(-3\right)^4}=-27\Rightarrow\left(-3\right)^{n-4}=\left(-3\right)^3\Rightarrow n-4=3\Rightarrow n=7\)

c,\(8^n:2^n=4\Rightarrow4^n=4\Rightarrow n=1\)

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

=> n - 4 = 3 => n = 7

c) 8n : 2n = 4

4n = 4.

a, 16/2n=2

<=>2n=8

<=>n=4

b, (-3)^n =-27*81=-2187

n=7( vì (-3)^7 =-2187

c, 8^n : 2^n =4

<=> (8:2)^n=4

4^n=4

n=1

a) \(\frac{16}{2^n}=2\)

=> 16 = 2 . 2ⁿ 

=> 16 = 2ⁿ⁺¹

=> 2⁴ = 2ⁿ⁺¹

=> n + 1 = 4

=> n = 4 - 1

=> n = 3

Vậy n = 3

b) \(\frac{\left(-3\right)^n}{81}=-27\)

=> (-3)ⁿ = -27 . 81

=> (-3)ⁿ = (-3)³ . (-3)⁴

=> (-3)ⁿ = (-3)⁷

=> n = 7

Vậy n = 7

c) 8ⁿ : 2² =  bao nhiêu vậy ban?

Chuk bn hk tốt!

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

    \(\Rightarrow16:2=2^n\) 

         2ⁿ=8=2³

Vậy n=3

b)\(\frac{\left(-3\right)^n}{81}=-27\)

  \(\Rightarrow\)(-3)ⁿ=-27.81

      (-3)ⁿ=-2187=(-3)⁷

Vậy n=7

c)Mk ko hiểu bn ghi gì

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

\(\Rightarrow2^n=\frac{16}{2}=8=2^3\)

\(\Rightarrow n=3\)

b) \(\frac{\left(-3\right)^n}{81}=27\)

\(\Rightarrow\left(-3\right)^n=-27.81=-2187=\left(-3\right)^7\)

\(\Rightarrow n=7\)
c) thiếu đề