a) \(2^{x+2}-2^x=96\)
\(\Rightarrow2^x\left(2^2-1\right)=96\)
\(\Rightarrow2^x.3=96\)
\(\Rightarrow2^x=32\)
\(\Rightarrow2^x=2^5\Rightarrow x=5\)
b) \(2^{x-1}+4.2^x=9.2^5\)
\(\Rightarrow2^x\left(2^{-1}+4\right)=288\)
\(\Rightarrow2^x.\dfrac{9}{2}=288\)
\(\Rightarrow2^x=64\)
\(\Rightarrow2^x=2^6\Rightarrow x=6\)