`tt\color{#36648B}{\text{#Yuuri}`

`2.`

`a)` `(x+7)^2 = 36`

`⇔` $\left[\begin{matrix} (x+7)^2 = 6^2\\ (x+7)^2 = (-6)^2\end{matrix}\right.$

`⇔` $\left[\begin{matrix} x+7 = 6\\ x+7 =-6\end{matrix}\right.$

`⇔` $\left[\begin{matrix} x=-1\\ x =-13\end{matrix}\right.$

   Vậy : `x ∈ { -1;-13 }`.

`b)` `2. (x+3)^2 - 24 = -6`

`⇔` `2. (x+3)^2 = 18`

`⇔` `(x+3)^2 = 9`

`⇔` $\left[\begin{matrix} (x+3)^2 = 3^2\\ (x+3)^2 = (-3)^2\end{matrix}\right.$

`⇔` $\left[\begin{matrix} x+3 = 3\\ x+3 =-3\end{matrix}\right.$

`⇔` $\left[\begin{matrix} 0=-1\\ x =-6\end{matrix}\right.$

   Vậy : `x ∈ { 0;-6 }`.