1. The problem statement, all variables and given/known data A 4.0μC charge is situated at the origin of an xy coordinate system. What is the potential difference between the points x=4.0m and y=2.0m because of this charge? 2. Relevant equations V = k X q/r 3. The attempt at a solution So i got the absolute value of the voltage to be 9.0 X 103. Howver how do you know if the voltage is negative or positive?