\(\left(2x-1\right)^2-4x^2+3=0\)
\(\Leftrightarrow4x^2-4x+1-4x^2+3=0\)
\(\Leftrightarrow-4x+4=0\)
\(\Leftrightarrow-4x=-4\)
=> x=1
Vậy....
\(\left(x-2\right)^2-9=0\)
\(\Leftrightarrow\left(x-2+3\right)\left(x-2-3\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(x-5\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=-1\\x=5\end{matrix}\right.\)
Vậy....
\(x^3-6x^2+12x-8=0\)
\(\Leftrightarrow\left(x-2\right)^3\)=0
\(\Leftrightarrow x=2\)