Given
Center at (-3,3)
A (1/2,6)
Use the formula for determining the midpoint to solve for point B
[tex]\begin{gathered} C=\Big(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2}\Big) \\ \left(-3,3\right)=\Big(\frac{0.5+x}{2},\frac{6+y}{2}\Big) \\ \\ -3=\frac{0.5+x}{2} \\ -6=0.5+x \\ -6-0.5=x \\ -6.5=x \\ -\frac{13}{2}=x \\ x=-\frac{13}{2}=-6.5 \\ \\ 3=\frac{6+y}{2} \\ 6=6+y \\ 6-6=y \\ 0=y \\ y=0 \end{gathered}[/tex]Therefore, point B is located at (-6.5 , 0).