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