Answer:
E = (Ay-2Bx) i ^ + (Ax + C) j ^ + 0 k ^ Â and (-C / A i ^ + 2BC / A2 j ^)
Explanation:
The electric field the electric potential are related through the least gradient
      E = -ΔV = - dV / dx i^
Let's perform the calculations
    E = dB / dx i ^ + dV / d and j ^ + dV / dz k ^
    dv / dx = A and - B 2x
    dv / dy = Ax + C
    dv / dz = 0
    E = (Ay-2Bx) i ^ + (Ax + C) j ^ + 0 k ^
Where is E = 0
      Ex = 0
      Ay -2Bx = 0
      y = 2B / A X
      Ey = 0
      Ax + C =
      x = -C / A
      Ez = 0
For the total electric field to be steel the two components must be zero simultaneously
      y = 2B / A (-C / A)
     y = 2B C / A2
The coordinates of the point are (-C / A i ^ + 2BC / A2 j ^)