`~rai~`
`(x-5)/-10=(-10)/(x-5)`
`⇔(x-5)(x-5)=(-10).(-10)`
`⇔(x-5)^2=100`
`⇔` \(\left[ \begin{array}{l}x-5=10\\x-5=-10\end{array} \right.\)
`⇔`\(\left[ \begin{array}{l}x=10+5\\x=-10+5\end{array} \right.\)
`⇔`\(\left[ \begin{array}{l}x=15\\x=-5\end{array} \right.\) .
`text{Vậy x∈{15;-5}.}`