\(\Leftrightarrow4.2^{x+1}.2^{x+1}-5.2^{x+1}+1=0\).Đặt t=\(2^{x+1}\).PT thành
\(4t^2-5t+1=0\)
\(\Leftrightarrow4t^2-4t-t+1=0\)
\(\Leftrightarrow4t\left(t-1\right)-\left(t-1\right)=0\)
\(\Leftrightarrow\left(4t-1\right)\left(t-1\right)=0\Rightarrow\left[{}\begin{matrix}t=\frac{1}{4}\\t=1\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}2^{x+1}=1\\2^{x+1}=\frac{1}{4}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-3\end{matrix}\right.\)