根据韦达定理得知
x1+x2=-b/a=6
x1x2=c/a=5
所以,x1²+x2²=(x1+x2)²-2x1x2=36-10=26
x2/x1+x1/x2=(x2²+x1²)/x1x2=26/5
(x1-x2)²=x1²-2x1x2+x2²=26-10=16
(x1-3)(x2-3)=x1x2-3(x1+x2)+9=5-18+9=-4
根据韦达定理得知
x1+x2=-b/a=6
x1x2=c/a=5
所以,x1²+x2²=(x1+x2)²-2x1x2=36-10=26
x2/x1+x1/x2=(x2²+x1²)/x1x2=26/5
(x1-x2)²=x1²-2x1x2+x2²=26-10=16
(x1-3)(x2-3)=x1x2-3(x1+x2)+9=5-18+9=-4