What is the electric potential at point x
A +0.605 mC charge is 0.113 m from point x, a -0.398 mC charge is 0.174 m from point x, and a -0.211 mC charge is 0.251 m from point x. What is the electric potential at point x? What is the resistance of a device rated 30 watts @ 120 volts DC?