判别式=[-(2k-1)]?-4k?
=4k?-4k+1-4k?
=-4k+1
所以-4k+11/4无解
-4k+1=0,k=1/4
则x?/4+x/2+1/4=0
(x/2+1/2)?
x=-1
-4k+1>0,k