\(4^{2x^2}-2.4^{x^2+x}+4^{2x}=0\)
\(\Leftrightarrow\left(4^{x^2}\right)^2-2.4^{x^2}.4^x+\left(4^x\right)^2=0\)
\(\Leftrightarrow\left(4^{x^2}-4^x\right)^2=0\)
\(\Leftrightarrow4^{x^2}=4^x\)
\(\Leftrightarrow x^2=x\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)