Four point charges, each of charge 2.5 x 10 -5 C, are located on the x- and y-axes, one at each of the locations (0, 2.0 m), (0, -2.0 m), (2.0 m, 0), and (-2.0 m, 0). The potential at the origin is

Answer 1

Potential is a scalar, so just add each component.
V=kq/distance=4*q/(4piEpislolon)2= 5e-5*8.98e-9 volts.
check my math/