Série 2 : exo 6d

[1, -3, 0, -1,  0, -2]
[0,  1, 0,  0, -4,  1]
[0,  0, 0,  1,  9,  4]
[0,  0, 0,  0,  0,  0]

L_1 <- L_1 + 1 * L_3

[1, -3, 0, 0,  9, 2]
[0,  1, 0, 0, -4, 1]
[0,  0, 0, 1,  9, 4]
[0,  0, 0, 0,  0, 0]

L_1 <- L_1 + 3 * L_2

[1, 0, 0, 0, -3, 5]
[0, 1, 0, 0, -4, 1]
[0, 0, 0, 1,  9, 4]
[0, 0, 0, 0,  0, 0]