行列式
t -1 -1
-1 t -1
-1 -1 t
c1+c2+c3
t-2 -1 -1
t-2 t -1
t-2 -1 t
r2-r1,r3-r1
t-2 -1 -1
0 t+1 0
0 0 t+1
= (t-2)(t+1)^2
所以 t=2 或 t=-1.
行列式
t -1 -1
-1 t -1
-1 -1 t
c1+c2+c3
t-2 -1 -1
t-2 t -1
t-2 -1 t
r2-r1,r3-r1
t-2 -1 -1
0 t+1 0
0 0 t+1
= (t-2)(t+1)^2
所以 t=2 或 t=-1.