`(x-5)^6``=``(x-5)^8`
`(x-5)^8``-``(x-5)^6``=``0`
`(x-5)^6``.``(x-5)^2``-``(x-5)^6``=``0`
`(x-5)^6`.`[(x-5)^2-1]``=``0`
`⇔`\(\left[ \begin{array}{l}(x-5)^6=0\\(x-5)^2-1=0\end{array} \right.\)
`⇔`\(\left[ \begin{array}{l}x-5=0\\(x-5)^2=1\end{array} \right.\)
`⇔`\(\left[ \begin{array}{l}x=5\\x-5=1\\x-5=-1\end{array} \right.\)
`⇔`\(\left[ \begin{array}{l}x=5\\x=6\\x=4\end{array} \right.\)