How did you do that? Show the three components of force exerted on 'q'.
Since Q and 4q are the same distance from q, perhaps little calculation is required.
two point charges of charge value Q AND q are placed at a Distance of x and x/2 respectively from a third charge of charge value 4q all charges being in the same straight line calculate the magnitude and nature of charge Q such that the net force experienced by charge q is zero
i first balanced force between q and Q and 4q and q is it right