\(a,\frac{16}{2^n}=2\Rightarrow2^n=16:2\Rightarrow2^n=8\Rightarrow2^n=2^3\Rightarrow n=3\)
\(b,\frac{\left(-3\right)^n}{81}=-27\Rightarrow\left(-3\right)^n=81.\left(-27\right)\Rightarrow\left(-3\right)^n=-2187\Rightarrow3^n=3^7\Rightarrow n=7\)
\(c,8^n:2^n=4\Rightarrow4^n=4\Rightarrow n=1\)
\(a,\frac{16}{2^n}=2\) \(b,\frac{\left(-3\right)^n}{81}=-27\) \(c,8^n:2^n=4\)
\(\Rightarrow2^4=2^n.2\) \(\Rightarrow\left(-3\right)^n=\left(-27\right).81\) \(\Rightarrow\left(8:2\right)^n=4\)
\(\Rightarrow4=n+1\) \(\Rightarrow\left(-3\right)^n=\left(-3\right)^7\) \(\Rightarrow4^n=4\)
\(\Rightarrow n=4-1=3\) \(\Rightarrow n=7\) \(\Rightarrow n=1\)