\(8.16\ge2^n\ge4\) => \(2^3.2^4\ge2^n\ge2^2\)=> \(2^7\ge2^n\ge2^2\)
=> \(7\ge n\ge2\)
=> \(n\in\left\{2;3;4;5;6;7\right\}\)
\(8.16\ge2^n\ge4\)
\(\Leftrightarrow2^3.2^4\ge2^n\ge2^2\)
\(\Leftrightarrow2^7\ge2^n\ge2^2\)
\(\Rightarrow2\le n\le7\)
\(\Rightarrow n\varepsilon\left\{2;3;4;5;6;7\right\}\)
\(8\times16\ge2^n\ge4\)
\(\Leftrightarrow128\ge2^n\ge4\)
\(\Leftrightarrow2^7\ge2^n\ge2^2\)
\(\Leftrightarrow7\ge x\ge2\)
\(\Leftrightarrow x\in(7,6,5,4,3,2)\)
Vậy \(x\in(7,6,5,4,3,2)\)
Bài làm
8 . 16 > 2n > 4
=> 128 > 2n > 4
=> 27 > 2n > 22
=> n C { 7; 5; 6; 4; 3; 2 }
# Học tốt #