1: ĐKXĐ: \(x\notin\left\{2;-2;0\right\}\)
\(A=\left(\dfrac{4x}{2+x}+\dfrac{8x^2}{4-x^2}\right):\left(\dfrac{x-1}{x^2-2x}-\dfrac{2}{x}\right)\)
\(=\left(\dfrac{4x}{x+2}-\dfrac{8x^2}{\left(x-2\right)\left(x+2\right)}\right):\left(\dfrac{x-1}{x\left(x-2\right)}-\dfrac{2}{x}\right)\)
\(=\dfrac{4x\left(x-2\right)-8x^2}{\left(x+2\right)\left(x-2\right)}:\dfrac{x-1-2\left(x-2\right)}{x\left(x-2\right)}\)
\(=\dfrac{-4x^2-8x}{\left(x+2\right)\left(x-2\right)}\cdot\dfrac{x\left(x-2\right)}{x-1-2x+4}\)
\(=\dfrac{-4x\left(x+2\right)\cdot\left(x-2\right)}{\left(x+2\right)\left(x-2\right)}\cdot\dfrac{x}{-x+3}=\dfrac{4x^2}{x-3}\)
2: A=-1
=>\(4x^2=-x+3\)
=>\(4x^2+x-3=0\)
=>\(4x^2+4x-3x-3=0\)
=>(x+1)(4x-3)=0
=>\(\left[{}\begin{matrix}x=-1\left(nhận\right)\\x=\dfrac{3}{4}\left(nhận\right)\end{matrix}\right.\)
