Use the method of elementary row operations described in Example 13.7.2 in order to calculate the inverse, provided it exists, for each of the three matrices:
(a) A = ([1, 2], [3,4]
(b) B = ([1, 2, 3], [2, 4, 5], [3, 5, 6])
(b) C = ([3, 2, - 1], [ - 1, 5, 8], [ - 9, - 6,3])
(a) A = ([1, 2], [3,4]
(b) B = ([1, 2, 3], [2, 4, 5], [3, 5, 6])
(b) C = ([3, 2, - 1], [ - 1, 5, 8], [ - 9, - 6,3])