A行列式【a,2c,3d,4e】＝8,B行列式为【b,c,d,e】＝-1abcde均为一维列向量,求A-B答案是 -4

A行列式【a,2c,3d,4e】＝8,B行列式为【b,c,d,e】＝-1abcde均为一维列向量,求A-B答案是 -4
A行列式【a,2c,3d,4e】＝8,B行列式为【b,c,d,e】＝-1abcde均为一维列向量,求A-B答案是 -4

A行列式【a,2c,3d,4e】＝8,B行列式为【b,c,d,e】＝-1abcde均为一维列向量,求A-B答案是 -4
|A-B|
= |a-b,c,2d,3e|
= 6|a-b,c,d,e|
= 6(|a,c,d,e|+|-b,c,d,e|)
= 6((1/(2*3*4))|a,2c,3d,4e|-|b,c,d,e|)
= 6((1/24 |A| - |B|)
= 6(1/3 + 1)
= 8
答案怎么是-4呢.
|B|=1 时答案为 -4.