a: \(\Leftrightarrow\left\{{}\begin{matrix}x>=0\\\left(3x-2\right)^2-\left(2x\right)^2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x>=0\\\left(x-2\right)\left(5x-2\right)=0\end{matrix}\right.\)
hay \(x\in\left\{2;\dfrac{2}{5}\right\}\)
b: \(\Leftrightarrow\left\{{}\begin{matrix}x< =0\\\left(2x+4\right)^2-\left(4x\right)^2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x< =0\\\left(-2x+4\right)\left(6x+4\right)=0\end{matrix}\right.\)
hay x=-2/3
c: \(\Leftrightarrow\left\{{}\begin{matrix}x< =21\\\left(2x-3\right)^2-\left(x-21\right)^2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x< =21\\\left(2x-3-x+21\right)\left(2x-3+x-21\right)=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x< =21\\\left(x+18\right)\left(3x-24\right)=0\end{matrix}\right.\Leftrightarrow x\in\left\{-18;8\right\}\)
d: \(\Leftrightarrow\left\{{}\begin{matrix}x>=2\\\left(3x-1-x+2\right)\left(3x-1+x-2\right)=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x>=2\\\left(2x+1\right)\left(4x-3\right)=0\end{matrix}\right.\Leftrightarrow x\in\varnothing\)