Two point charges q1 = -3 nC and q2 = -27 nC are at x = 0 and x = 25 cm, respectively, and free to move. A third charge is placed so that the entire three-charge system is in static equilibrium. What are the magnitude, sign, and x-coordinate of the third charge?
a) What is the magnitude of the third charge?
b) What is the sign of the third charge?
c) What is the position of the third charge?