`3 : (x - 3)^2 - 5 = - 4,25`
`⇔ 3 : (x - 3)^2 = 5 - 4,25 = 0,75`
`⇔ (x - 3)^2 = 3 : 0,75 = 4`
`⇒` \(\left[ \begin{array}{l}x - 3 = 2\\x - 3 = -2\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l}x=5\\x=1\end{array} \right.\)
`text(Vậy)` `S = { 1 ; 5}`