3. (Exercise 7.26 from Dasgupta, Papadimitriou & Vazirani) In a satisfiable system of linear inequalities we describe the jth inequality as forced-equal if it is satisfied with equality by every solution x = (zi, ,xn) of the system. Equivalent, ?ajizi-bj is not forced-equal if there exists an x that satisfies the whole system and such that ? ajiTK bj For example, in C1 1 2 0 the first two inequalities are forced-equal, while the third and fourth are not. A solution x to the system is called characteristic if, for every inequality I that is not forced-equal, x satisfies I without equality. In the instance above, such a solution is (x1,22) - (-1,3), foir which xi