x=(根号3-根号2)/(根号3+根号2),y=(根号3+根号2)(根号3-根号2),求代数式3x^2-5xy+3y^2的值

x=(√2-√3)/(√3+√2)=(√2-√3)*(√3-√2)/((√3+√2)*(√3-√2))=(-5+2√6)/(3-2) =-5+2√6y=(√3+√2)/(√3-√2)=(√3+√2)*(√3+√2)/(√3-√2)*(√3+√2)) =(5+2√6)/(3-2) =5+2√6x*y=(√2-√3)/(√3+√2)*(...9到10排x*y为什么等余-1？你这片是抄的，我正在看，但还是请你解释下，谢谢！x*y=(√2-√3)/(√3+√2)*(√3+√2)/(√3-√2) =1那是写错了吗？还是全部错了？√2-√3与√3-√2看错了全部错了哦，但 x*y=(√2-√3)/(√3+√2)*(√3+√2)/(√3-√2) = -1 3x^2-5x*y+3y^2 =3(x^2-2x*y+y^2)+x*y =3(x-y)^2+x*y =3(-5+2√6-(5+2√6))^2+(-1) =3(-5+2√6-5-2√6)^2+(-1) =3(-10)^2-1 =300-1 =299 上面的都是对的吗？没法改了知道了，全部错了x=5-2√6 y=5+2√6 x*y=13x^2-5x*y+3y^2 =3(x^2-2x*y+y^2)+x*y =3(x-y)^2+x*y =3(5-2√6-(5+2√6))^2+1=3(-4√6)^2+1=3*16*6+1=289