2 1 5 8 3 9 6 3 0 9 D3 D 0 2 5 2 0 2 5 0 6 7 0 2 7, = 2 7 D 81 108 1 3, D 27 D 27 D 2 7 D,27 xA=-4= D27 D27 上1 4 0 6 0 2 5 2 1 3 9 6 2 1 8 1 3 − − − D = = −27, 1 4 7 0 0 2 1 5 1 3 0 9 2 1 5 8 4 − − − − − D = = 27, 3, 27 81 1  1 = = = D D x 4, 27 108 2 2 = − − = = D D x 1, 27 27 3 3 = − − = = D D x 1. 27 4 27 4 = = = D D x