将系数写成行列式:
[ (a-1) 4 ]
[ 3 2 ]
令D=
[ (a-1) 4 ]
[ 3 2 ]
=(a-1)*2-3*4=2a-14
若D=0,即a=7,方程无解.
若D不等于0.
令Dx=
[ 1 4 ]
[ 2 2 ]
=-6
Dy=
[ (a-1) 1 ]
[ 3 2 ]
=2a-5
则x=Dx/D=3/(7-a)
y=Dy/D=(2a-5)/(2a-14)
将系数写成行列式:
[ (a-1) 4 ]
[ 3 2 ]
令D=
[ (a-1) 4 ]
[ 3 2 ]
=(a-1)*2-3*4=2a-14
若D=0,即a=7,方程无解.
若D不等于0.
令Dx=
[ 1 4 ]
[ 2 2 ]
=-6
Dy=
[ (a-1) 1 ]
[ 3 2 ]
=2a-5
则x=Dx/D=3/(7-a)
y=Dy/D=(2a-5)/(2a-14)