Ta có:
\(\frac{x-1}{-4}=\frac{-25}{x-1}\)
\(\Rightarrow\left(x-1\right).\left(x-1\right)=-4.\left(-25\right)\)
\(\Rightarrow\left(x-1\right)^2=100\)
\(\Rightarrow\left(x-1\right)^2=\left(\pm10\right)^2\)
\(\Rightarrow\left[{}\begin{matrix}x-1=10\Rightarrow x=11\\x-1=-10\Rightarrow x=-9\end{matrix}\right.\)
Vậy \(x\in\left\{10;-9\right\}\)