A.x²-110/3x+1/9=0 B.x²-110/3x-1/9=0 C.x²+110/3x+1/9=0 D.x²-1/9x-110/3=0
解：
由韦达定理得
x1+x2=-(-18)/3=6 x1·x2=-1/3
x1²+x2²=(x1+x2)²-2x1·x2=6²雀纯-2·(-1/3)=110/3
x1²·x2²=(x1·x2)²=(-1/3)²=1/9
设所求方程x²+ax+b=0，罩岁世两根为x1²，x2²，由韦达定物肢理得
-a=x1²+x2²
b=x1²·x2²
a=-(x1²+x2²)=-110/3
b=x1²·x2²=1/9
所求方程为x²-(110/3)x+1/9=0
选A
由题设，x1+x2=6
x1*x2=-1/3
所以或租x1^2*x2^2=1/9
(x1)^2+(x2)^2=(x1+x2)^2-2(x1)(x2)=36+2/棚团圆3=110/3
因此应选链塌A