Question

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Answer 1

đk : x khác -2 ; 2 ; -1 

\(P=\dfrac{x+2-4}{x^2-4}\left(\dfrac{x+2}{x+1}\right)=\dfrac{1}{x+2}.\dfrac{x+2}{x+1}=\dfrac{1}{x+1}\)

Answer 2

\(P=\left(\dfrac{1}{x-2}-\dfrac{4}{x^2-4}\right).\left(1+\dfrac{1}{x+1}\right)\)

\(\Rightarrow P=\left(\dfrac{x+2}{\text{​​}\left(x-2\right)\left(x+2\right)}-\dfrac{4}{\left(x-2\right)\left(x+2\right)}\right).\left(\dfrac{x+1}{x+1}+\dfrac{1}{x+1}\right)\)

\(\Rightarrow P=\dfrac{x+2-4}{\text{​​}\left(x-2\right)\left(x+2\right)}.\dfrac{x+1+1}{x+1}\)

\(\Rightarrow P=\dfrac{x-2}{\text{​​}\left(x-2\right)\left(x+2\right)}.\dfrac{x+2}{x+1}\)

\(\Rightarrow P=\dfrac{1}{x+1}\)

Answer 3

\(P=\dfrac{x+2-4}{\left(x+2\right)\left(x-2\right)}\cdot\dfrac{x+1+1}{x+1}=\dfrac{x-2}{\left(x+2\right)\left(x-2\right)}\cdot\dfrac{x+2}{x+1}=\dfrac{1}{x+1}\)