Question

Answer 1

1) ĐKXĐ: \(x\ne1,x\ne-1\)

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

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

3) \(A=\dfrac{2}{x-1}=\dfrac{2}{5-1}=\dfrac{2}{4}=\dfrac{1}{2}\)

4) \(A=\dfrac{2}{x-1}\in Z\Rightarrow\left(x-1\right)\inƯ\left(2\right)=\left\{-2;-1;1;2\right\}\)

Kết hợp với ĐKXĐ \(\Rightarrow x\in\left\{0;2;3\right\}\)

Answer 2

ĐKXĐ \(x\ne1;-1\)