Water is flowing through a network of pipes (in thousands of cubic meters per hour), as shown in the figure. (Assume F1 = 600 and F2 = 500. If the system has an infinite number of solutions, express X1, X2, X3, X4, X5, X6, and x7 in terms of the parameters s and t.) X2 P2 X3 XA X'S . F2 X7 (a) Solve this system for the water flow represented by X;, i = 1, 2, . . ., 7. (X1, X2, X3, X4, X5, X6, X7) = (b) Find the water flow when X1 = X2 = 200. (X1, X2, X3, X4, X5, X6, X7) = (c) Find the water flow when X6 = X7 = 0. (X1, X2, X3, X4, X5, X6, X7) = (d) Find the water flow when x5 = 1000 and x6 = 0. (X1, X2, X3, X4, X5, X6, X7) =