To find the point where the electric field is zero between two charges, Q1 (+9 nC) and Q2 (+4 nC), it's essential to analyze the regions along the x-axis. The electric fields from both charges must cancel each other out, which can occur either to the left of Q1, between the charges, or to the right of Q2. The discussion emphasizes the importance of drawing field vectors to visualize where cancellation might occur. Additionally, the potential at x = -5 and the work needed to move Q2 from x = 5 to x = 3 are related to understanding electric potential and work done against electric fields. Understanding these concepts is crucial for solving the problem effectively.