Question

Giúp em với huhu

Mai em cần luôn rồi

Answer 1

\(A=\dfrac{1}{1-x}-\dfrac{2x}{x^3+x-x^2-1}\)

\(\Leftrightarrow A=\dfrac{1}{1-x}-\dfrac{2x}{\left(x^3-x^2\right)+\left(x-1\right)}\)

\(\Leftrightarrow A=\dfrac{1}{1-x}-\dfrac{2x}{x^2\left(x-1\right)+\left(x-1\right)}\)

\(\Leftrightarrow A=\dfrac{1}{1-x}-\dfrac{2x}{\left(x-1\right)\left(x^2+1\right)}\)

\(\Leftrightarrow A=\dfrac{1}{1-x}+\dfrac{2x}{\left(1-x\right)\left(x^2+1\right)}\)

\(\Leftrightarrow A=\dfrac{x^2+1}{\left(1-x\right)\left(x^2+1\right)}+\dfrac{2x}{\left(1-x\right)\left(x^2+1\right)}\)

\(\Leftrightarrow A=\dfrac{x^2+1+2x}{\left(1-x\right)\left(x^2+1\right)}\)

\(\Leftrightarrow A=\dfrac{\left(x+1\right)^2}{\left(1-x\right)\left(x^2+1\right)}\) ( cho hỏi kiểm tra đề có sai ko vậy, để mình làm tiếp )