m为有理数,x^2-4(m-1)x+3m^2-2m+2k=0的根是有理数,则
方程的判别式≥0,即
[-4(m-1)]^2-4(3m^2-2m+2k)≥0
k≤[(m-3)^2-5]/2
m=3,k最小值=-2.5
k≥-2.5
答:k≥-2.5