1 1 3 1
-1 1 -1 3
5 -2 8 -9
-1 3 1 7
r2+r1,r3-5r1,r4+r1
1 1 3 1
0 2 2 4
0 -7 -7 -14
0 4 4 8
r2*(1/2),r3-7r2,r4-4r2
1 1 3 1
0 1 1 2
0 0 0 0
0 0 0 0
所以矩阵的秩为2.
1 1 3 1
-1 1 -1 3
5 -2 8 -9
-1 3 1 7
r2+r1,r3-5r1,r4+r1
1 1 3 1
0 2 2 4
0 -7 -7 -14
0 4 4 8
r2*(1/2),r3-7r2,r4-4r2
1 1 3 1
0 1 1 2
0 0 0 0
0 0 0 0
所以矩阵的秩为2.