Two charges, q1 and q2, are located at the origin and at (0.50 m, 0), respectively. Where

Question:

Two charges, q1 and q2, are located at the origin and at (0.50 m, 0), respectively. Where on the x-axis must a third charge, q3, of arbitrary sign be placed to be in electrostatic equilibrium if
(a) q1 and q2 are like charges of equal magnitude,
(b) q1 and q2 are unlike charges of equal magnitude, and
(c) q1 = + 3.0 μC and q2 = – 7.0μC?