1) There are two charges located at (0, 2m) and (-4m, 0) with magnitudes of 5mC and -3mC respectively. 2) The net electric field at the origin is calculated by adding the electric field contributions from each charge. 3) The electric field from each charge is calculated using Coulomb's Law and the direction is determined by the position of the charge relative to the origin. 4) The net electric field is -1687500 i^ - 11250000 j^ and has a magnitude of 11375858.5 N/C.