1MS : 2.5.21 k

[1, -1, -1,  6]
[1, -2, -3, 10]
[5,  6,  1,  2]

L_2 <- L_2 - 1 * L_1

[1, -1, -1, 6]
[0, -1, -2, 4]
[5,  6,  1, 2]

L_3 <- L_3 - 5 * L_1

[1, -1, -1,   6]
[0, -1, -2,   4]
[0, 11,  6, -28]

L_3 <- L_3 + 11 * L_2

[1, -1,  -1,  6]
[0, -1,  -2,  4]
[0,  0, -16, 16]

L_2 <- -1 * L_2

[1, -1,  -1,  6]
[0,  1,   2, -4]
[0,  0, -16, 16]

L_3 <- -1/16 * L_3

[1, -1, -1,  6]
[0,  1,  2, -4]
[0,  0,  1, -1]