please solve questions 3 and 4

Q3. Consider single-facility rectilinear minisum location problem. Four existing facilities are located at (7,4),(4,6),(9,10),(12,6). The weights are 30,40,55, and 80 respectively. a) Write the mathematical formulation of the problem in open form. b) Sketch the graphs of the objective functions for the x and y variables. c) Determine the optimum coordinates. 1 Q4. Four existing facilities located at P1=(8,12),P2=(10,13),P3=(11,7) and P4=(7,6) with w1=50,w2=80,w3=100 and w4=7. a) Determine the optimum location for a single new facility by using squared Euclidean distances. b) Draw the contour line passing through the point (8,10) and calculate the objective function value at this point