2^-1.2ⁿ+4.2ⁿ=9.2⁵

=>2^n-1+2².2ⁿ=9.2⁵

=>2^n-1+2ⁿ⁺²=9.2⁵

=>2^n-1.(2³+1)=9.2⁵

=>2^n-1.9=9.2⁵

=>2^n-1=2⁵

=>n-1=5=>n=6

Ta có: \(2^{-1}\cdot2^n+4\cdot2^n=9\cdot2^5\)

\(\Leftrightarrow2^n\cdot2^{-1}+2^n\cdot2^2=9\cdot2^5\)

\(\Leftrightarrow2^n\cdot\left(2^{-1}+2^2\right)=9\cdot2^5\)

\(\Leftrightarrow2^n\cdot\dfrac{9}{2}=9\cdot2^5\)

\(\Leftrightarrow2^n=9\cdot2^5:\dfrac{9}{2}=2^5\cdot9\cdot\dfrac{2}{9}=2^6\)

hay n=6

Vậy: n=6

\(\frac{1}{2}.2^n+4.2^n=9.2^5\)

\(2^n.\left(\frac{1}{2}.4\right)=288\)

\(2^n.2=288\)

\(2^n=288:2\)

\(2^n=144\)

       Suy ra n ko tìm được

Ta có : 

\(\frac{1}{2}\cdot2^n+4\cdot2^n=\frac{9}{2}\cdot2^5\)

\(=>\left(\frac{1}{2}+4\right)\cdot2^n=9\cdot2^5\)

\(=>\left(\frac{1}{2}+\frac{8}{2}\right)\cdot2^n=9\cdot2^5\)

\(=>\frac{9}{2}\cdot2^n=\frac{9}{2}\cdot2^5\)

\(=>2^n=2^5\)

\(=>n=5\)

\(\frac{1}{2}\times2^n+4\times2^n=9\times2^5\)

\(2^n\times\left(\frac{1}{2}+4\right)=9\times2^5\)

\(2^n\times\left(\frac{1+8}{4}\right)=9\times2^5\)

\(2^n\times\frac{9}{2^2}=9\times2^5\)

\(\frac{2^n}{2^2}=2^5\)

\(2^n=2^5\times2^2\)

\(2^n=2^7\)

\(n=7\)

a) \(\frac{1}{9}.27^n=3^n\)

\(=>\frac{27^n}{9}=3^n\)

\(=>3^n=3^n=>n=1\)

b) \(2^{-1}.2^n+4.2^n=9.2^5\)

\(=>2^{n-1}.2^2.2^n=9.2^5\)

\(=>2^{n-1}.2^{2+n}=9.2^5\)

\(=>2^{2n+1}=9.5^2\)

\(=>n=\)

Câu b đề sai hay sao ấy số xấu lắm

a)1/9.27^n=3^n

             3^n=3^n

         =>n={0;1;2;3;...}     

a) n= 2;3;5;7;...(n là số nguyên)

 a)1/9.27^n=3^n

 3^n=3^n

=>n={0;1;2;3...}

 Tích nha ^_^ !!!

c) 3^{n + 2} - 3^{n + 1} = 1458

=> 3ⁿ . 3² - 3ⁿ . 3¹ = 1458

=> 3ⁿ (3² - 3) = 1458

=> 3ⁿ . 6 = 1458

=> 3ⁿ = 243

=> n = 5

d) 2^{n - 1} + 4.2ⁿ = 9.2⁵

=> 2ⁿ . 2¹ + 4.2ⁿ = 9.2⁵

=> 2ⁿ (2 + 4) = 9.2⁵

=> 2ⁿ . 6 = 9.2⁵

=> 2ⁿ = \(\frac{9\cdot2^5}{6}=48\)

=> không tìm được x

a, 9.27ⁿ=3ⁿ

    3².3³ⁿ=3ⁿ

    3²⁺³ⁿ=3ⁿ

     2+3n=n

     n-3n=2

     -2n=2

       n=-1

bạn nhớ k cho mk nha

b, (2³:4).2ⁿ=4

    (2³:2²).2ⁿ=2²

      2¹.2ⁿ=2²

      2¹⁺ⁿ = 2²

       1+n=2

          n=1

bạn nhớ k cho minh nha

vậy c và d đâu rùi bạn