Điều kiện: \(x\ge1\)
\(\dfrac{\sqrt{x-1}}{\sqrt{x}+1}=2\\ \Leftrightarrow\sqrt{x-1}=2\sqrt{x}+2\\ \Rightarrow x-1=4x+4+8\sqrt{x}\\ \Leftrightarrow3x+8\sqrt{x}+5=0\\ \Leftrightarrow\left(\sqrt{x}+1\right)\left(3\sqrt{x}+5\right)=0\\\Leftrightarrow\left[{}\begin{matrix}\sqrt{x}=-1\\\sqrt{x}=-\dfrac{3}{5}\end{matrix}\right.\left(loại\right)} \)