Let x1, x2, x3 be binary variables with the following relationship: x1 x2 x3 0 0 0 0 1 1 1 0 1 1 1 0 Table 1: Truth table for XOR operation (a) In the following formulation correct? Explain what each constraint is doing? (1 x1) + x2 + x3 1 2 x1 + (1 x2) + x3 1 2 x1 + x2 + (1 x3) 1 2 (1 x1) + (1 x2) + (1 x3) 1 2 (b) Can you write a formulation using one equation? Hint: You may need to use an additional variable