a)
ĐKXĐ \(\left(x\ge1\right)\)
\(\Leftrightarrow2x-2\sqrt{x^2-2x+1}=\dfrac{x^2+6x+9}{4}\)
\(8x-8\left(x-1\right)=x^2+6x+9\)
\(\Leftrightarrow x^2+6x-1=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3-\sqrt{10}\left(l\right)\\x=\sqrt{10}-3\left(tm\right)\end{matrix}\right.\)