a: Sửa đề: căn x+1
\(M=\dfrac{-\sqrt{x}\left(\sqrt{x}+1\right)+\sqrt{x}\left(\sqrt{x}-1\right)-\sqrt{x}+3}{x-1}\)
\(=\dfrac{-x-\sqrt{x}+x-\sqrt{x}-\sqrt{x}+3}{x-1}=\dfrac{-3\left(\sqrt{x}-1\right)}{x-1}\)
\(=-\dfrac{3}{\sqrt{x}+1}\)
b: M nguyên khi \(\sqrt{x}+1\in\left\{1;-1;3;-3\right\}\)
=>x=0 hoặc x=4