1MS : 2.5.21 i

[7, -4, -5, 56]
[0,  3, -2, 13]
[5, -3,  0, 22]

L_3 <- 7 * L_3

[ 7,  -4, -5,  56]
[ 0,   3, -2,  13]
[35, -21,  0, 154]

L_3 <- L_3 - 5 * L_1

[7, -4, -5,   56]
[0,  3, -2,   13]
[0, -1, 25, -126]

L_2 <- L_2 + 3 * L_3

[7, -4, -5,   56]
[0,  0, 73, -365]
[0, -1, 25, -126]

L_2 <-> L_3

[7, -4, -5,   56]
[0, -1, 25, -126]
[0,  0, 73, -365]

L_3 <- 1/73 * L_3

[7, -4, -5,   56]
[0, -1, 25, -126]
[0,  0,  1,   -5]

L_2 <- -1 * L_2

[7, -4,  -5,  56]
[0,  1, -25, 126]
[0,  0,   1,  -5]