Question

Rút gọn:

\(\left[\dfrac{3}{x+1}+\left(\dfrac{3}{x+1}-\dfrac{x}{1+2x+x^2}\right):\dfrac{2x^3+3x^2}{x+1}\right]:\dfrac{3x+1}{x^3+x^2}:\left(x-1\right)\)