a: \(A=\dfrac{x\left(x+1\right)}{\left(x-1\right)^2}:\dfrac{x^2-1+x+2-x^2}{x\left(x-1\right)}\)
\(=\dfrac{x\left(x+1\right)}{\left(x-1\right)^2}\cdot\dfrac{x\left(x-1\right)}{x+1}=\dfrac{x^2}{x-1}\)
b:Khi x=2 thì \(A=\dfrac{4}{2-1}=4\)
c: Để M là số nguyên thì x2-1+1 chia hết cho x-1
=>1 chia hết cho x-1
=>\(x-1\in\left\{1;-1\right\}\)
hay x=2