A charge of -1 C is at the origin. How much energy would be applied to or released from a  -1 C charge if it is moved from  (-7 ,1 )  to (-1 ,4 ) ?

Initial distance between the two charges is $\sqrt{{\left(- 7\right)}^{2} + {\left(1\right)}^{2}}$ or $7.07 m$ and final distance is $\sqrt{{\left(- 1\right)}^{2} + {\left(4\right)}^{2}}$ i.e $4.12 m$
So, initial potential energy of the system is $\left(U 1\right) = 9 \cdot {10}^{9} \cdot \left(- 1\right) \cdot \frac{- 1}{7.07} J$ and final potential energy $\left(U 2\right) = 9 \cdot {10}^{9} \cdot \left(- 1\right) \cdot \frac{- 1}{4.12} J$
Clearly, $U 1$ is smaller than $U 2$
So, energy that has to be added is $U 2 - U 1$ = $9.1 \cdot {10}^{8} J$