\(\left\{{}\begin{matrix}x\ge8\\x-\sqrt{x-8}-3\sqrt{x}+1=0\end{matrix}\right.\)
\(\left(1-\sqrt{x-8}\right)+\left(x-3\sqrt{x}\right)=0\)
\(\dfrac{9-x}{1+\sqrt{x-8}}+\dfrac{x^2-9x}{x+3\sqrt{x}}=0\)
\(\left(9-x\right)\left(\dfrac{1}{1+\sqrt{x-8}}+\dfrac{x}{x+3\sqrt{x}}\right)=0\)
x>=8 => x =9 là duy nhất