1. The problem statement, all variables and given/known data In free space, Q1 = 10nc at P1(0,-4,0) and Q2 = 20nC at P2(0,0,4). a. Find E at the origin (answered) E(r) = 5.617ay - 11.235az b. Where should a 30nC point charge be located so E=0 at the origin? (need help) 2. Relevant equations E(r) = (1/4(pi)epsilon) sum ((Qm)am/(|r-rm|^2)) formula for electric field intensity 3. The attempt at a solution E = 0, Q3 = 30nC E = 0 = (1/4(pi)epsilon) ( (Q1)a1/(|r-r1|^2))+ ....) a3 = (0-x)ax + (0-y)ay + (0-z)az/ |r-r3| x = 0 P3 = (0, y, z) 5.617ay - 11.235 az = ((Q3)a3/(|r-r3|^2)) *5.617ay - 11.235 az = Q3((0-y)ay + (0-z)az/ |r-r3|^3) **|r-r3| = sqrt(0^2 + (0-y)^2 + (0-z)^2) * and ** aren't enough to solve I'm missing one thing any help would be appreciated.