(x-5) . (x-5)=25.4
(x-5) . (x-5)=100
10.10=100
Vậy x=15
\(\frac{x-5}{25}=\frac{4}{x-5}\)
\(\Leftrightarrow\left(x-5\right)\left(x-5\right)=25.4\)
\(\left(x-5\right)^2=100\)
\(\left(x-5\right)^2=\pm10^2\)
\(\Rightarrow\hept{\begin{cases}x-5=10\\x-5=-10\end{cases}\Rightarrow\hept{\begin{cases}x=15\\x=-5\end{cases}}}\)