a metre scale is place along the axis of a convex mirror of focal length25cm it's nearer and being at a distance of 50cm. calculate the size of image formed

Along the line connecting the two charges, at what distance from the charge q1 is the total electric field from the two charges zero? express your answer in terms of some or all of the variables s, q1, q2 and k =14ï€ïµ0. if your answer is difficult to enter, consider simplifying it, as it can be made relatively simple with some work.