根据韦达定理,x1+x2=-k/2 x1x2=(1-2k)/2
x1^2+x2^2
=(x1+x2)^2-2x1x2
=k^2/4-1+2k
=29/4
k^2-4+8k=29
k^2+8k-33=0
(k+11)(k-3)=0
k1=-11 k2=3
△=k^2+8(2k-1)=k^2+16k-8>=0
(k+8)^2>=72
k>=6√2-8或k<=-6√2-8
所以k=3