Thực hiện phép tính:
x+1x+2:(x+2x+3:x+3x+1)
= \(\dfrac{x+1}{x+2}:\left(\dfrac{x+2}{x+3}\cdot\dfrac{x+1}{x+3}\right)=\dfrac{x+1}{x+2}:\dfrac{\left(x+2\right)\left(x+1\right)}{\left(x+3\right)^2}=\dfrac{x+1}{x+2}\cdot\dfrac{\left(x+3\right)^2}{\left(x+2\right)\left(x+1\right)}=\dfrac{\left(x+3\right)^2}{\left(x+2\right)^2}\)