a, \(3^{-2}.3^4.3^3.3^n=3^7\)
\(\Rightarrow3^{-2+4+3+n}=3^7\)
\(\Rightarrow3^{5+n}=3^7\)
Vì \(3\ne-1;3\ne0;3\ne1\) nên \(5+n=7\Rightarrow x=2\)
Vậy....
b, \(2^{-1}.2^n+4.2^n=9.2^5\)
\(\Rightarrow2^n.\left(2^{-1}+2^2\right)=9.2^5\)
\(\Rightarrow2^n.4,5=9.32\)
\(\Rightarrow2^n=288:4,5\)
\(\Rightarrow2^n=64=2^6\)
Vì \(2\ne-1;2\ne0;2\ne1\) nên \(n=6\)
Vậy.....
c, \(2.16\ge2^n>4\)
\(\Rightarrow32\ge2^n>2^2\)
\(\Rightarrow2^5\ge2^n>2^2\)
Vì \(2\ne-1;2\ne0;2\ne1\) nên \(5\ge n>2\)
\(\Rightarrow n\in\left\{3;4;5\right\}\)
Vậy.....
Chúc bạn học tốt!!!
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