a) \(3^{x+1}=9^x\)
\(\Rightarrow3^{x+1}=\left(3.3\right)^x\)
\(\Rightarrow3^{x+1}=3^{3x}\)
\(\Rightarrow x+1=3x\)
\(\Rightarrow3x-x=2x=1\)
\(\Rightarrow x=1\)
b) \(2^{3x+2}=4^{x+5}\)
\(2^{3x+2}=\left(2.2\right)^{x+5}\)
\(\Rightarrow2^{3x+2}=2^{2\left(x+5\right)}=2^{2x+10}\)
\(\Rightarrow3x+2=2x+10\Rightarrow3x+2=2x+2+8\)
\(\Rightarrow3x=2x+8\Rightarrow3x-2x=8\)
\(\Rightarrow1x=8\Rightarrow x=8\)