Suppose that the augmented matrix of a linear system in variables x, y, and 2: has been partially reduced through elementary row operations to the following form: 1 7 2f e+f 0 1 56 2f 0 0 e 3' Find all values of e and f for which the system a) [1 mark] is inconsistent. b} [1 mark] has a unique solution. c) [1 mark] has infinitely many solutions