\begin{solution}
\Part{a}
\begin{equation}
- V_3 = k_e \frac{q_1}{r_13} + k_e \frac{q_2}{r_12}
+ V_3 = k_e \frac{q_1}{r_{13}} + k_e \frac{q_2}{r_{12}}
= 2 k_e \frac{2\U{$\mu$C}}{\sqrt{(1.00\U{m})^2 + (0.500\U{m})^2}}
= \ans{32.2\U{kV}}
\end{equation}