1. Formulettes with binary variables This problem uses the same binary decision variables as the Capital Budgeting model discussed during lecture. Recall that our decision variables in this formulation were xi,i=1,,7, where xi=1 if investment i is selected, and xi=0 if investment i is not selected. Write constraints that would enforce the following modifications to the Capital Budgeting model. Consider each modification independently of the others. a) If investment 1 is selected, investment 3 must also be selected. b) At least one of investments 6 and 7 must be selected. c) Investment 2 can only be selected if both investments 1 and 3 are selected. d) Let investments 1, 2,3, and 4 represent stocks, and investments 5, 6, and 7 represent bonds. At least twice as many stocks must be selected than bonds