`~rai~`
\(a)(x+3)(2x-1)-2(x-1)^2=0\\\Leftrightarrow 2x^2-x+6x-3-2(x^2-2x+1)=0\\\Leftrightarrow 2x^2-x+6x-3-2x^2+4x-2=0\\\Leftrightarrow 9x-5=0\\\Leftrightarrow 9x=5\\\Leftrightarrow x=\dfrac{5}{9}.\\\text{Vậy x=}\dfrac{5}{9}.\\b)(x+3)^2-(x-1)^2=5\\\Leftrightarrow x^2+6x+9-(x^2-2x+1)=5\\\Leftrightarrow x^2+6x+9-x^2+2x-1=5\\\Leftrightarrow 8x+8=5\\\Leftrightarrow 8x=-3\\\Leftrightarrow x=-\dfrac{3}{8}.\\\text{Vậy x=}-\dfrac{3}{8}.\\c)x^2-6x=0\\\Leftrightarrow x(x-6)=0\\\Leftrightarrow \left[\begin{array}{I}x=0\\x-6=0\end{array}\right.\\\Leftrightarrow \left[\begin{array}{I}x=0\\x=6.\end{array}\right.\\\text{Vậy x}\in\{0;6\}.\)
