\(\Leftrightarrow\left(x-5\right)^4\cdot\left[\left(x-5\right)^2-1\right]=0\)
=>(x-5)(x-4)(x-6)=0
=>\(x\in\left\{4;5;6\right\}\)
`@` `\text {Ans}`
`\downarrow`
`(x-5)^4 = (x-5)^6`
`=> (x-5)^4 - (x-5)^6 = 0`
`=> (x-5)^4 - (x-5)^2 (x-5)^4 = 0`
`=> (x-5)^4 * [ 1 - (x-5)^2] = 0`
`=> (x-5)^4 * [ (x-4)(x-6)] = 0`
`=> (x-5)(x-4)(x-6) = 0`
`=>`\(\left[{}\begin{matrix}x-5=0\\x-4=0\\x-6=0\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=5\\x=4\\x=6\end{matrix}\right.\)
Vậy, `x \in {5; 4; 6}.`