是2k-6
判别式等于0
[-(2k-6)]²-4(k-3)=0
4k²-24k+36-4k+12=0
k²-7k+12=0
(k-3)(k-4)=0
k=3,k=4
k=3
x²=0
x1=x2=0
k=4
x²-2x+1=(x-1)²=0
x1=x2=1
是2k-6
判别式等于0
[-(2k-6)]²-4(k-3)=0
4k²-24k+36-4k+12=0
k²-7k+12=0
(k-3)(k-4)=0
k=3,k=4
k=3
x²=0
x1=x2=0
k=4
x²-2x+1=(x-1)²=0
x1=x2=1