Final answer:
The question lacks sufficient context to determine the coordinates of vertex F". Without additional information or a diagram, it is not possible to provide an accurate answer.
Step-by-step explanation:
The student is asking about the coordinates of vertex F in a mathematical context, likely related to geometry or coordinate systems. However, the question lacks specific details or context about figure F"G"H" that would enable us to determine the coordinates of vertex F". The information provided revolves around vector calculations and displacement vectors, which does not directly help us to find the coordinates of a vertex without additional information about its relation to the vectors mentioned. Therefore, we cannot accurately determine the correct coordinates for vertex F" without context or a diagram showing the relative positions of the points or the vectors describing their positions.