Algorithm analysis and design

Q1: In The Single-Source Shortest Paths we using three algorithm, When we used every one of that tree algorithm (Bellman-Ford - Shortest Paths in DAGs - Dijkstra's ) ? Q2: In The All -pairs shortest-paths we using three algorithm , When we used every one of that tree algorithm (Matrix multiplication- Floyd-Warshall algorithm - Johnson's algorithm ) ? Q3: Find The Single-Source Shortest Paths of the following graph using 1- Bellman-Ford the start vertex is A Write the solution step by step and change color of Shortest path in the graph