Bài 2: ĐKXĐ: \(x\notin\left\{2;-2\right\}\)
\(B=\left(\dfrac{2}{x-2}-\dfrac{1}{x^2-4}\right):\dfrac{1}{x+2}\)
\(=\left(\dfrac{2}{x-2}-\dfrac{1}{\left(x-2\right)\left(x+2\right)}\right):\dfrac{1}{x+2}\)
\(=\dfrac{2\left(x+2\right)-1}{\left(x-2\right)\left(x+2\right)}\cdot\dfrac{x+2}{1}\)
\(=\dfrac{2x+4-1}{x-2}=\dfrac{2x+3}{x-2}\)
Bài 3: ĐKXĐ: \(x\notin\left\{2;-2\right\}\)
\(C=\left(\dfrac{2}{x-2}-\dfrac{1}{x+2}\right)\cdot\dfrac{x^2+4x+4}{8}\)
\(=\dfrac{2\left(x+2\right)-x+2}{\left(x-2\right)\left(x+2\right)}\cdot\dfrac{\left(x+2\right)^2}{8}\)
\(=\dfrac{2x+4-x+2}{\left(x-2\right)}\cdot\dfrac{1}{8}=\dfrac{x+6}{8\left(x-2\right)}\)
