1. The problem involves analyzing a network of avenues and streets with given distances and variables $x_1$, $x_2$, $x_3$, and $x_4$ representing unknown distances or flows. 2. The user requests to use their own data, not the professor's data, so we focus on the distances and variables as given: - 1re Avenue: 70 and 60 units - Rue Principale: 160 from start to A, then 200 from B - Rue de l'Église: 40, 20, and 110 units - Variables $x_1$, $x_2$, $x_3$, $x_4$ are placed on the paths between points A, B, C, D 3. To solve or analyze, we need to set up equations based on the network, such as flow conservation or distance sums, using the user's data. 4. For example, if these represent flows, the sum of flows into a node equals the sum out; if distances, total distances along paths can be expressed in terms of $x_i$. 5. Without explicit question, the best approach is to write equations using the user's data: - At node A: $x_1 + 160 = x_4 + 200$ - At node C: $x_2 + 40 = 130 + x_4$ - At node D: $x_3 + 20 = 110$ 6. These equations can be solved for $x_1$, $x_2$, $x_3$, $x_4$ if needed. Final answer: The problem requires using the user's data to set up and solve equations involving $x_1$, $x_2$, $x_3$, and $x_4$ based on the given distances and network structure.