\(a,2.16\le2^n< 4\)
\(\Rightarrow2^5\le2^n< 2^2\)
\(\Rightarrow n\in5,4,3\)
\(b,3^2.3^n=3^5\)
\(\Rightarrow3^n=3^5:3^2\)
\(\Rightarrow3^n=3^2\)
\(\Rightarrow n=2\)
\(c,\left(2^2:4\right):2^n=4\)
\(\Rightarrow1:2^n=4\)
\(\Rightarrow2^n=1:4=\frac{1}{4}\)
mà \(n\in N\)nên n ko có giá trị nào
\(d,\frac{1}{9}.3^4.3^n=3^7\)
\(\Rightarrow\left(\frac{1}{3}\right)^2.3^2.3^2.3^n=3^7\)
\(\Rightarrow3^2.3^n=3^7\)
\(\Rightarrow3^n=3^7:3^2\)
\(\Rightarrow3^n=3^5\)
\(\Rightarrow n=5\)
e,f làm tự làm tiếp nhé,mỏi tay wa
a,2.16 =32
32\(\ge\)2n >4\(\Rightarrow\)25\(\ge\)2n>22
Vậy n \(\in\){5;4;3}