急急急!!!求解一道4阶行列式,要详细过程(拍照最好)
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c2+2c1,c3+c1,c4-4c1
5 14 7 -19
2 7 3 -10
-5 -17 -8 29
1 0 0 0
按第4行展开
= (-1)^(4+1)*
14 7 -19
7 3 -10
-17 -8 29
r3+r1
14 7 -19
7 3 -10
-3 -1 10
c1-3c2,c3+10c2
-7 7 51
-2 3 20
0 -1 0
= -(-1)*(-1)^(3+2)*
-7 51
-2 20
= - (-140+102)
= 38
5 14 7 -19
2 7 3 -10
-5 -17 -8 29
1 0 0 0
按第4行展开
= (-1)^(4+1)*
14 7 -19
7 3 -10
-17 -8 29
r3+r1
14 7 -19
7 3 -10
-3 -1 10
c1-3c2,c3+10c2
-7 7 51
-2 3 20
0 -1 0
= -(-1)*(-1)^(3+2)*
-7 51
-2 20
= - (-140+102)
= 38
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