\(a,x^2-6x+6=0\)
\(\Leftrightarrow\left(x^2+6x+9\right)-3=0\)
\(\Leftrightarrow\left(x+3\right)^2-3=0\)
\(\Leftrightarrow\left(x+3-\sqrt{3}\right)\left(x+3+\sqrt{3}\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\sqrt{3}-3\\-\sqrt{3}-3\end{matrix}\right.\)
\(b,3x^2-2x\sqrt{3}-3=0\)
\(\Leftrightarrow\left(x\sqrt{3}-1\right)^2-4=0\)
\(\Leftrightarrow\left(x\sqrt{3}-1-2\right)\left(x\sqrt{3}-1+2\right)=0\)
\(\Leftrightarrow\left(x\sqrt{3}-3\right)\left(x\sqrt{3}+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\sqrt{3}\\x=\frac{-\sqrt{3}}{3}\end{matrix}\right.\)
