\(=\dfrac{x^2+2x+x+2}{x+1}=\dfrac{\left(x+2\right)\left(x+1\right)}{x+1}=x+2\)
x2+3x+\(\dfrac{2}{x+1}\)
= \(\dfrac{x^2\left(x+1\right)}{x+1}+\dfrac{3x\left(x+1\right)}{x+1}+\dfrac{2}{x+1}\)
= \(\dfrac{x^3+x^2}{x+1}+\dfrac{3x^2+3x}{x+1}+\dfrac{2}{x+1}\)
= \(\dfrac{x^3+x^2+3x^2+3x+2}{x+1}\)
= \(\dfrac{\left(x^3+x^2\right)+\left(3x^2+3x\right)+2}{x+1}\)
= \(\dfrac{x^2\left(x+1\right)+3x\left(x+1\right)+2}{x+1}\)
= \(\dfrac{\left(x+1\right)\left(x^2+3x\right)+2}{x+1}\)
= \(x^2+3x+2\)
bài này ghi rõ chút cái đề nhìn vô biết là \(\dfrac{x^2+3x+2}{x+1}\)hay là\(x^2+3x+\dfrac{2}{x+1}\)
