Three point charges, $+2\ \mu\text{C}$, $+2\ \mu\text{C}$ and $-2\ \mu\text{C}$, are placed at the corners of an equilateral triangle of side $30\ \text{cm}$. Take $\dfrac{1}{4\pi\varepsilon_0} = 9 \times 10^9\ \text{N m}^2\,\text{C}^{-2}$. The electrostatic potential energy of this arrangement (the work needed to bring the charges together from far apart) is