ĐKXĐ: \(x\ge1\)
Đặt \(\left\{{}\begin{matrix}\sqrt{x-1}=a\ge0\\\sqrt{x^2+x+1}=b>0\end{matrix}\right.\)
\(\Leftrightarrow ab+1=a+b\)
\(\Leftrightarrow ab-a-\left(b-1\right)=0\)
\(\Leftrightarrow\left(a-1\right)\left(b-1\right)=0\Leftrightarrow\left[{}\begin{matrix}a=1\\b=1\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}\sqrt{x-1}=1\\\sqrt{x^2+x+1}=1\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=2\\x=0\\x=-1\left(l\right)\end{matrix}\right.\)