Question

1111/12-14/2-3-1-5/312 11

Answer 1

2-r1,r3 - 2r1,r4 - 3r1 得

1 1 1 1;0 1 -2 3; 0 -5 -3 -7; 0 -2 -1 8

r3+5r2,r4+2r2

1 1 1 1; 0 1 -2 3; 0 0 -13 8; 0 0 -5 14

r4 - (5/13)r3

1 1 1 1; 0 1 -2 3; 0 0 -13 8; 0 0 0 142/13

= -142