Nil General Online What Charge Q3 & Position Vector R3 Be Placed If Chrges Q1 & Q2 With Posnn Vctors R1 & R2 To Exp. Nil Force?

What charge q3 & position vector r3 be placed if Chrges q1 & q2 with posnn vctors r1 & r2 to exp. nil force? - nil general online

Charges Q1 and Q2 are in the plan, is the general term for loading into Q3 with R3 vector so that the burden does not charge any q3 force.ie Q3 experince Q1 = f (, R1, Q2, R2)
R3 = g (T1, R1, Q2, R2)