a) ĐKXĐ: \(x\ne0;x\ne\pm1\)
Ta có: \(A=\left(\dfrac{1}{x^2+x}-\dfrac{2-x}{x+1}\right).\dfrac{x}{x+1}\)
\(A=\left[\dfrac{1}{x\left(x+1\right)}-\dfrac{2-x}{x+1}\right].\dfrac{x}{x+1}\)
\(A=\dfrac{1-x\left(2-x\right)}{x\left(x+1\right)}.\dfrac{x}{x+1}\)
\(A=\dfrac{1-2x+x^2}{x\left(x+1\right)}.\dfrac{x}{x+1}\)
\(A=\dfrac{\left(1-x\right)^2}{\left(x+1\right)^2}\)