`3(x+3)^2 - 10 = 17`
`<=> 3(x+3)^2 = 17 + 10`
`<=> 3(x+3)^2 = 27`
`<=> (x+3)^2 = 27 : 3`
`<=> (x+3)^2 = 9`
`<=> (x+3)^2 = (±3)^2`
`<=> ` \(\left[ \begin{array}{l}x+3=3\\x+3=-3\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x=0\\x=-6\end{array} \right.\)
Vậy `x∈{0;-6}`