\(P=\left(\dfrac{x+1}{1-x}-\dfrac{1-x}{1+x}-\dfrac{4x^2}{x^2-1}\right):\dfrac{4x^2-4}{x^2-2x+1}\)
\(=\left(\dfrac{\left(x+1\right)\left(1+x\right)}{\left(1-x\right)\left(1+x\right)}-\dfrac{\left(1-x\right)\left(1-x\right)}{\left(1-x\right)\left(1+x\right)}+\dfrac{4x^2}{\left(1-x\right)\left(1+x\right)}\right):\dfrac{4\left(x-1\right)\left(x+1\right)}{\left(x-1\right)^2}\)
\(=\left(\dfrac{\left(1+x\right)^2-\left(1-x\right)^2+4x^2}{\left(1-x\right)\left(1+x\right)}\right):\dfrac{4\left(x+1\right)}{x-1}\)
\(=\dfrac{4x^2+4x}{\left(1-x\right)\left(1+x\right)}:\dfrac{4\left(x+1\right)}{x-1}\)
\(=\dfrac{4x}{1-x}:\dfrac{4\left(x+1\right)}{x-1}\)
\(=\dfrac{4x}{1-x}\times\dfrac{x-1}{4\left(x+1\right)}\)
\(=-\dfrac{4x}{4\left(x+1\right)}\)
Chúc bạn học tốt !!
