$\left( S \right):{{x}^{2}}+{{y}^{2}}+{{z}^{2}}-2x+4y-6z-2=0$

Suy ra $I\left( 1;-2;3 \right)$ và bán kính $R=\sqrt{{{1}^{2}}+{{\left( -2 \right)}^{2}}+{{3}^{2}}+2}=4$.

Chú ý: Mặt cầu $(S):{{x}^{2}}+{{y}^{2}}+{{z}^{2}}+ax+by+cz+d=0\to \left\{ \begin{align} & I\left( \frac{a}{-2};\frac{b}{-2};\frac{c}{-2} \right) \\ & R=\sqrt{\frac{{{a}^{2}}+{{b}^{2}}+{{c}^{2}}}{4}-d} \\ \end{align} \right.$